@article{lee_zhao_peterson_parsons_2017, title={Catalytic "MOF-Cloth" Formed via Directed Supramolecular Assembly of UiO-66-NH2 Crystals on Atomic Layer Deposition-Coated Textiles for Rapid Degradation of Chemical Warfare Agent Simulants}, volume={29}, ISSN={["1520-5002"]}, DOI={10.1021/acs.chemmater.7b00949}, abstractNote={Highly tunable metal–organic framework (MOF) materials, including, for example, UiO-66-NH2, are known to be effective catalysts to degrade chemical warfare agents (CWAs) with half-lives near 1 min. Therefore, many researchers have been actively working on producing supported MOF materials to improve application effectiveness by using relatively slow solvothermal synthesis or repetitious stepwise layer-by-layer methods. Herein, we demonstrate a facile route to rapidly assemble presynthesized UiO-66-NH2 crystals onto nonwoven polypropylene (PP) fibrous mats at ambient temperature. Crystal assembly is chemically directed using β-cyclodextrin (β-CD) and cetyltrimethylammonium bromide (CTAB) as surfactant assembly agents, where the agents quickly (within 5 min) self-assemble on the crystal surface and promote physically robust chemical surface attachment while simultaneously impeding solution-phase crystal agglomeration. Furthermore, we find that when the PP is preconditioned using conformal metal oxide thin f...}, number={11}, journal={CHEMISTRY OF MATERIALS}, author={Lee, Dennis T. and Zhao, Junjie and Peterson, Gregory W. and Parsons, Gregory N.}, year={2017}, month={Jun}, pages={4894–4903} }
 @article{huang_li_gurarslan_yu_kirste_guo_zhao_collazo_sitar_parsons_et al._2016, title={Atomically Thin MoS2 Narrowband and Broadband Light Superabsorbers}, volume={10}, ISSN={["1936-086X"]}, url={http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:000381959100030&KeyUID=WOS:000381959100030}, DOI={10.1021/acsnano.6b02195}, abstractNote={We present a combined theoretical and experimental effort to enable strong light absorption (>70%) in atomically thin MoS2 films (≤4 layers) for either narrowband incidence with arbitrarily prespecified wavelengths or broadband incidence like solar radiation. This is achieved by integrating the films with resonant photonic structures that are deterministically designed using a unique reverse design approach based on leaky mode coupling. The design starts with identifying the properties of leaky modes necessary for the targeted strong absorption, followed by searching for the geometrical features of nanostructures to support the desired modes. This process is very intuitive and only involves a minimal amount of computation, thanks to the straightforward correlations between optical functionality and leaky modes as well as between leaky modes and the geometrical feature of nanostructures. The result may provide useful guidance for the development of high-performance atomic-scale photonic devices, such as solar cells, modulators, photodetectors, and photocatalysts.}, number={8}, journal={ACS NANO}, author={Huang, Lujun and Li, Guoqing and Gurarslan, Alper and Yu, Yiling and Kirste, Ronny and Guo, Wei and Zhao, Junjie and Collazo, Ramon and Sitar, Zlatko and Parsons, Gregory N. and et al.}, year={2016}, month={Aug}, pages={7493–7499} }
 @article{lemaire_zhao_williams_walls_shepherd_losego_peterson_parsons_2016, title={Copper Benzenetricarboxylate Metal-Organic Framework Nucleation Mechanisms on Metal Oxide Powders and Thin Films formed by Atomic Layer Deposition}, volume={8}, ISSN={["1944-8244"]}, url={http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:000374274900078&KeyUID=WOS:000374274900078}, DOI={10.1021/acsami.6b01195}, abstractNote={Chemically functional microporous metal-organic framework (MOF) crystals are attractive for filtration and gas storage applications, and recent results show that they can be immobilized on high surface area substrates, such as fiber mats. However, fundamental knowledge is still lacking regarding initial key reaction steps in thin film MOF nucleation and growth. We find that thin inorganic nucleation layers formed by atomic layer deposition (ALD) can promote solvothermal growth of copper benzenetricarboxylate MOF (Cu-BTC) on various substrate surfaces. The nature of the ALD material affects the MOF nucleation time, crystal size and morphology, and the resulting MOF surface area per unit mass. To understand MOF nucleation mechanisms, we investigate detailed Cu-BTC MOF nucleation behavior on metal oxide powders and Al2O3, ZnO, and TiO2 layers formed by ALD on polypropylene substrates. Studying both combined and sequential MOF reactant exposure conditions, we find that during solvothermal synthesis ALD metal oxides can react with the MOF metal precursor to form double hydroxy salts that can further convert to Cu-BTC MOF. The acidic organic linker can also etch or react with the surface to form MOF from an oxide metal source, which can also function as a nucleation agent for Cu-BTC in the mixed solvothermal solution. We discuss the implications of these results for better controlled thin film MOF nucleation and growth.}, number={14}, journal={ACS APPLIED MATERIALS & INTERFACES}, author={Lemaire, Paul C. and Zhao, Junjie and Williams, Philip S. and Walls, Howard J. and Shepherd, Sarah D. and Losego, Mark D. and Peterson, Gregory W. and Parsons, Gregory N.}, year={2016}, month={Apr}, pages={9514–9522} }
 @article{tovar_zhao_nunn_barton_peterson_parsons_levan_2016, title={Diffusion of CO2 in Large Crystals of Cu-BTC MOF}, volume={138}, ISSN={["0002-7863"]}, url={http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:000383410700007&KeyUID=WOS:000383410700007}, DOI={10.1021/jacs.6b05930}, abstractNote={Carbon dioxide adsorption in metal-organic frameworks has been widely studied for applications in carbon capture and sequestration. A critical component that has been largely overlooked is the measurement of diffusion rates. This paper describes a new reproducible procedure to synthesize millimeter-scale Cu-BTC single crystals using concentrated reactants and an acetic acid modulator. Microscopic images, X-ray diffraction patterns, Brunauer-Emmett-Teller surface areas, and thermogravimetric analysis results all confirm the high quality of these Cu-BTC single crystals. The large crystal size aids in the accurate measurement of micropore diffusion coefficients. Concentration-swing frequency response performed at varying gas-phase concentrations gives diffusion coefficients that show very little dependence on the loading up to pressures of 0.1 bar. The measured micropore diffusion coefficient for CO2 in Cu-BTC is 1.7 × 10(-9) m(2)/s.}, number={36}, journal={JOURNAL OF THE AMERICAN CHEMICAL SOCIETY}, author={Tovar, Trenton M. and Zhao, Junjie and Nunn, William T. and Barton, Heather F. and Peterson, Gregory W. and Parsons, Gregory N. and LeVan, M. Douglas}, year={2016}, month={Sep}, pages={11449–11452} }
 @article{zhao_lee_yaga_hall_barton_woodward_oldham_walls_peterson_parsons_2016, title={Ultra-Fast Degradation of Chemical Warfare Agents Using MOF-Nanofiber Kebabs}, volume={55}, ISSN={["1521-3773"]}, url={http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:000385799200053&KeyUID=WOS:000385799200053}, DOI={10.1002/anie.201606656}, abstractNote={Abstract}, number={42}, journal={ANGEWANDTE CHEMIE-INTERNATIONAL EDITION}, author={Zhao, Junjie and Lee, Dennis T. and Yaga, Robert W. and Hall, Morgan G. and Barton, Heather F. and Woodward, Ian R. and Oldham, Christopher J. and Walls, Howard J. and Peterson, Gregory W. and Parsons, Gregory N.}, year={2016}, month={Oct}, pages={13224–13228} }
 @article{stano_faraji_hodges_yildiz_wells_akyildiz_zhao_jur_bradford_2016, title={Ultralight Interconnected Metal Oxide Nanotube Networks}, volume={12}, ISSN={["1613-6829"]}, DOI={10.1002/smll.201503267}, abstractNote={Record-breaking ultralow density aluminum oxide structures are prepared using a novel templating technique. The alumina structures are unique in that they are comprised by highly aligned and interconnected nanotubes yielding anisotropic behavior. Large-scale network structures with complex form-factors can easily be made using this technique. The application of the low density networks as humidity sensing materials as well as thermal insulation is demonstrated.}, number={18}, journal={SMALL}, author={Stano, Kelly L. and Faraji, Shaghayegh and Hodges, Ryan and Yildiz, Ozkan and Wells, Brian and Akyildiz, Halil I. and Zhao, Junjie and Jur, Jesse and Bradford, Philip D.}, year={2016}, month={May}, pages={2432–2438} }
 @article{wang_zhao_bagal_dandley_oldham_fang_parsons_chang_2016, title={Wicking Enhancement in Three-Dimensional Hierarchical Nanostructures}, volume={32}, ISSN={["0743-7463"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84982307197&partnerID=MN8TOARS}, DOI={10.1021/acs.langmuir.6b01864}, abstractNote={Wicking, the absorption of liquid into narrow spaces without the assistance of external forces, has drawn much attention due to its potential applications in many engineering fields. Increasing surface roughness using micro/nanostructures can improve capillary action to enhance wicking. However, reducing the structure length scale can also result in significant viscous forces to impede wicking. In this work, we demonstrate enhanced wicking dynamics by using nanostructures with three-dimensional (3D) hierarchical features to increase the surface area while mitigating the obstruction of liquid flow. The proposed structures were engineered using a combination of interference lithography and hydrothermal synthesis of ZnO nanowires, where structures at two length scales were independently designed to control wicking behavior. The fabricated hierarchical 3D structures were tested for water and ethanol wicking properties, demonstrating improved wicking dynamics with intermediate nanowire lengths. The experimental data agree with the derived fluid model based on the balance of capillary and vicious forces. The hierarchical wicking structures can be potentially used in applications in water harvesting surfaces, microfluidics, and integrated heat exchangers.}, number={32}, journal={LANGMUIR}, author={Wang, Zhiting and Zhao, Junjie and Bagal, Abhijeet and Dandley, Erinn C. and Oldham, Christopher J. and Fang, Tiegang and Parsons, Gregory N. and Chang, Chih-Hao}, year={2016}, month={Aug}, pages={8029–8033} }
 @article{zhao_gong_nunn_lemaire_stevens_sidi_williams_oldham_walls_shepherd_et al._2015, title={Conformal and highly adsorptive metal-organic framework thin films via layer-by-layer growth on ALD-coated fiber mats}, volume={3}, ISSN={["2050-7496"]}, url={http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:000346906100014&KeyUID=WOS:000346906100014}, DOI={10.1039/c4ta05501b}, abstractNote={Fiber@ALD@MOF structures fabricated via ALD and layer-by-layer MOF synthesis show good conformality and high adsorption capacity.}, number={4}, journal={JOURNAL OF MATERIALS CHEMISTRY A}, author={Zhao, Junjie and Gong, Bo and Nunn, William T. and Lemaire, Paul C. and Stevens, Eric C. and Sidi, Fahim I. and Williams, Philip S. and Oldham, Christopher J. and Walls, Howard J. and Shepherd, Sarah D. and et al.}, year={2015}, pages={1458–1464} }
 @article{zhao_nunn_lemaire_lin_dickey_oldham_walls_peterson_losego_parsons_et al._2015, title={Facile Conversion of Hydroxy Double Salts to Metal-Organic Frameworks Using Metal Oxide Particles and Atomic Layer Deposition Thin-Film Templates}, volume={137}, ISSN={["1520-5126"]}, url={http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:000364355900009&KeyUID=WOS:000364355900009}, DOI={10.1021/jacs.5b08752}, abstractNote={Rapid room-temperature synthesis of metal-organic frameworks (MOFs) is highly desired for industrial implementation and commercialization. Here we find that a (Zn,Cu) hydroxy double salt (HDS) intermediate formed in situ from ZnO particles or thin films enables rapid growth (<1 min) of HKUST-1 (Cu3(BTC)2) at room temperature. The space-time-yield reaches >3 × 10(4) kg·m(-3)·d(-1), at least 1 order of magnitude greater than any prior report. The high anion exchange rate of (Zn,Cu) hydroxy nitrate HDS drives the ultrafast MOF formation. Similarly, we obtained Cu-BDC, ZIF-8, and IRMOF-3 structures from HDSs, demonstrating synthetic generality. Using ZnO thin films deposited via atomic layer deposition, MOF patterns are obtained on pre-patterned surfaces, and dense HKUST-1 coatings are grown onto various form factors, including polymer spheres, silicon wafers, and fibers. Breakthrough tests show that the MOF-functionalized fibers have high adsorption capacity for toxic gases. This rapid synthesis route is also promising for new MOF-based composite materials and applications.}, number={43}, journal={JOURNAL OF THE AMERICAN CHEMICAL SOCIETY}, publisher={American Chemical Society (ACS)}, author={Zhao, Junjie and Nunn, William T. and Lemaire, Paul C. and Lin, Yiliang and Dickey, Michael and Oldham, Christopher J. and Walls, Howard J. and Peterson, Gregory W. and Losego, Mark D. and Parsons, Gregory N. and et al.}, year={2015}, month={Nov}, pages={13756–13759} }
 @article{bagal_dandley_zhao_zhang_oldham_parsons_chang_2015, title={Multifunctional nano-accordion structures for stretchable transparent conductors}, volume={2}, ISSN={["2051-6355"]}, url={http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:000359586600003&KeyUID=WOS:000359586600003}, DOI={10.1039/c5mh00070j}, abstractNote={Nano-accordion structures allow brittle materials to stretch, enabling transparent conductors that are stretchable and flexible.}, number={5}, journal={MATERIALS HORIZONS}, author={Bagal, Abhijeet and Dandley, Erinn C. and Zhao, Junjie and Zhang, Xu A. and Oldham, Christopher J. and Parsons, Gregory N. and Chang, Chih-Hao}, year={2015}, month={Sep}, pages={486–494} }
 @article{zhang_bagal_dandley_zhao_oldham_wu_parsons_chang_2015, title={Ordered 3D Thin-Shell Nanolattice Materials with Near-Unity Refractive Indices}, volume={25}, ISSN={["1616-3028"]}, url={http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:000365532100009&KeyUID=WOS:000365532100009}, DOI={10.1002/adfm.201502854}, abstractNote={The refractive indices of naturally occurring materials are limited, and there exists an index gap between indices of air and available solid materials. With many photonics and electronics applications, there has been considerable effort in creating artificial materials with optical and dielectric properties similar to air while simultaneously being mechanically stable to bear load. Here, a class of ordered nanolattice materials consisting of periodic thin‐shell structures with near‐unity refractive index and high stiffness is demonstrated. Using a combination of 3D nanolithography and atomic layer deposition, these ordered nanostructured materials have reduced optical scattering and improved mechanical stability compared to existing randomly porous materials. Using ZnO and Al2O3 as the building materials, refractive indices from 1.3 down to 1.025 are achieved. The experimental data can be accurately described by Maxwell Garnett effective media theory, which can provide a guide for index design. The demonstrated low‐index, low‐scattering, and high‐stiffness materials can serve as high‐quality optical films in multilayer photonic structures, waveguides, resonators, and ultra‐low‐k dielectrics.}, number={42}, journal={ADVANCED FUNCTIONAL MATERIALS}, author={Zhang, Xu A. and Bagal, Abhijeet and Dandley, Erinn C. and Zhao, Junjie and Oldham, Christopher J. and Wu, Bae-Ian and Parsons, Gregory N. and Chang, Chih-Hao}, year={2015}, month={Nov}, pages={6644–6649} }
 @article{zhao_serrano_franzen_2014, title={A Model for the Flexibility of the Distal Histidine in Dehaloperoxidase-Hemoglobin A Based on X-ray Crystal Structures of the Carbon Monoxide Adduct}, volume={53}, ISSN={["0006-2960"]}, DOI={10.1021/bi5001905}, abstractNote={Dehaloperoxidase hemoglobin A (DHP A) is a multifunctional hemoglobin that appears to have evolved oxidative pathways for the degradation of xenobiotics as a protective function that complements the oxygen transport function. DHP A possesses at least two internal binding sites, one for substrates and one for inhibitors, which include various halogenated phenols and indoles. Herein, we report the X-ray crystallographic structure of the carbonmonoxy complex (DHPCO). Unlike other DHP structures with 6-coordinated heme, the conformation of the distal histidine (H55) in DHPCO is primarily external or solvent exposed, despite the fact that the heme Fe is 6-coordinated. As observed generally in globins, DHP exhibits two distal histidine conformations (one internal and one external). In previous structural studies, we have shown that the distribution of H55 conformations is weighted strongly toward the external position when the DHP heme Fe is 5-coordinated. The large population of the external conformation of the distal histidine observed in DHPCO crystals at pH 6.0 indicates that some structural factor in DHP must account for the difference from other globins, which exhibit a significant external conformation only when pH < 4.5. While the original hypothesis suggested that interaction with a heme-Fe-bound ligand was the determinant of H55 conformation, the current study forces a refinement of that hypothesis. The external or open conformation of H55 is observed to have interactions with two propionate groups in heme, at distances of 3.82 and 2.73 Å, respectively. A relatively weak hydrogen bonding interaction between H55 and CO, combined with strong interactions with heme propionate (position 6), is hypothesized to strengthen the external conformation of H55. Density function theory (DFT) calculations were conducted to test whether there is a weaker hydrogen bond interaction between H55 and heme bonded CO or O2. Molecular dynamics simulations were conducted to examine how the tautomeric forms of H55 affect the dynamic motions of the distal histidine that govern the switching between open and closed conformations. The calculations support the modified hypothesis suggesting a competition between the strength of interactions with heme ligand and the heme propionates as the factors that determine the conformation of the distal histidine.}, number={15}, journal={BIOCHEMISTRY}, author={Zhao, Junjie and Serrano, Vesna and Franzen, Stefan}, year={2014}, month={Apr}, pages={2474–2482} }
 @article{zhao_losego_lemaire_williams_gong_atanasov_blevins_oldham_walls_shepherd_et al._2014, title={Highly adsorptive, MOF-functionalized nonwoven fiber mats for hazardous gas capture enabled by atomic layer deposition}, volume={1}, number={4}, journal={Advanced Materials Interfaces}, author={Zhao, J. J. and Losego, M. D. and Lemaire, P. C. and Williams, P. S. and Gong, B. and Atanasov, S. E. and Blevins, T. M. and Oldham, C. J. and Walls, H. J. and Shepherd, S. D. and et al.}, year={2014} }
 @article{schkolnik_utesch_zhao_jiang_thompson_mroginski_hildebrandt_franzen_2013, title={Catalytic efficiency of dehaloperoxidase A is controlled by electrostatics - application of the vibrational Stark effect to understand enzyme kinetics}, volume={430}, ISSN={["1090-2104"]}, DOI={10.1016/j.bbrc.2012.12.047}, abstractNote={The vibrational Stark effect is gaining popularity as a method for probing electric fields in proteins. In this work, we employ it to explain the effect of single charge mutations in dehaloperoxidase-hemoglobin A (DHP A) on the kinetics of the enzyme. In a previous communication published in this journal (BBRC 2012, 420, 733-737) it has been shown that an increase in the overall negative charge of DHP A through mutation causes a decrease in its catalytic efficiency. Here, by labeling the protein with 4-mercaptobenzonitrile (MBN), a Stark probe molecule, we provide further evidence that the diffusion control of the catalytic process arises from the electrostatic repulsion between the enzyme and the negatively charged substrate. The linear correlation observed between the nitrile stretching frequency of the protein-bound MBN and the catalytic efficiency of the single-site mutants of the enzyme indicates that electrostatic interactions play a dominant role in determining the catalytic efficiency of DHP A.}, number={3}, journal={BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS}, author={Schkolnik, Gal and Utesch, Tillmann and Zhao, Junjie and Jiang, Shu and Thompson, Matthew K. and Mroginski, Maria-Andrea and Hildebrandt, Peter and Franzen, Stefan}, year={2013}, month={Jan}, pages={1011–1015} }
 @article{zhao_srajer_franzen_2013, title={Functional Consequences of the Open Distal Pocket of Dehaloperoxidase-Hemoglobin Observed by Time-Resolved X-ray Crystallography}, volume={52}, ISSN={["0006-2960"]}, DOI={10.1021/bi401118q}, abstractNote={Using time-resolved X-ray crystallography, we contrast a bifunctional dehaloperoxidase-hemoglobin (DHP) with previously studied examples of myoglobin and hemoglobin to understand the functional role of the distal pocket of globins. One key functional difference between DHP and other globins is the requirement that H2O2 enter the distal pocket of oxyferrous DHP to displace O2 from the heme Fe atom and thereby activate the heme for the peroxidase function. The open architecture of DHP permits more than one molecule to simultaneously enter the distal pocket of the protein above the heme to facilitate the unique peroxidase cycle starting from the oxyferrous state. The time-resolved X-ray data show that the distal pocket of DHP lacks a protein valve found in the two other globins that have been studied previously. The photolyzed CO ligand trajectory in DHP does not have a docking site; rather, the CO moves immediately to the Xe-binding site. From there, CO can escape but can also recombine an order of magnitude more rapidly than in other globins. The contrast with DHP dynamics and function more precisely defines the functional role of the multiple conformational states of myoglobin. Taken together with the high reduction potential of DHP, the open distal site helps to explain how a globin can also function as a peroxidase.}, number={45}, journal={BIOCHEMISTRY}, author={Zhao, Junjie and Srajer, Vukica and Franzen, Stefan}, year={2013}, month={Nov}, pages={7943–7950} }
 @article{zhao_serrano_zhao_le_franzen_2013, title={Structural and Kinetic Study of an Internal Substrate Binding Site in Dehaloperoxidase-Hemoglobin A from Amphitrite ornata}, volume={52}, ISSN={["0006-2960"]}, DOI={10.1021/bi301307f}, abstractNote={X-ray crystal structures of dehaloperoxidase-hemoglobin A (DHP A) from Amphitrite ornata soaked with substrate, 2,4,6-tribromophenol (2,4,6-TBP), in buffer solvent with added methanol (MeOH), 2-propanol (2-PrOH), and dimethyl sulfoxide (DMSO) reveal an internal substrate binding site deep in the distal pocket above the α-edge of the heme that is distinct from the previously determined internal inhibitor binding site. The peroxidase function of DHP A has most often been studied using 2,4,6-trichlorophenol (2,4,6-TCP) as a substrate analogue because of the low solubility of 2,4,6-TBP in an aqueous buffer solution. Previous studies at low substrate concentrations pointed to the binding of substrate 2,4,6-TCP at an external site near the exterior heme β- or δ-edge as observed in the class of heme peroxidases. Here we report that the turnover frequencies of both substrates 2,4,6-TCP and 2,4,6-TBP deviate from Michaelis-Menten kinetics at high concentrations. The turnover frequency reaches a maximum in the range of 1400-1700 μM, with a decrease in rate at higher concentrations that is both substrate- and solvent-dependent. The X-ray crystal structure is consistent with the presence of an internal active site above the heme α-edge, in which the substrate would be oxidized in two consecutive steps inside the enzyme, followed by attack by H2O via a water channel in the protein. The physiological role of the internal site may involve interactions with any of a number of aromatic toxins found in benthic ecosystems where A. ornata resides.}, number={14}, journal={BIOCHEMISTRY}, author={Zhao, Jing and Serrano, Vesna and Zhao, Junjie and Le, Peter and Franzen, Stefan}, year={2013}, month={Apr}, pages={2427–2439} }
 @article{zhao_zhao_franzen_2013, title={The Regulatory Implications of Hydroquinone for the Multifunctional Enzyme Dehaloperoxidase-Hemoglobin from Amphitrite ornata}, volume={117}, ISSN={["1520-6106"]}, DOI={10.1021/jp407663n}, abstractNote={Hydroquinone (H2Q) has been observed to compete with the oxidation of substrates 2,4,6-tribromophenol (2,4,6-TBP) and 2,4,6-trichlorophenol (2,4,6-TCP) catalyzed by the dehaloperoxidase-hemoglobin (DHP) from Amphitrite ornata in the presence of H2O2. This competition is observed as a lag phase during which H2Q is preferentially oxidized to 1,4-benzoquinone (1,4-BQ) while totally inhibiting either 2,4,6-TBP or 2,4,6-TCP oxidation. The inhibition by H2Q is distinct from that of the native competitive inhibitor 4-bromophenol (4-BP) since H2Q is itself oxidized and its product 1,4-BQ is not an inhibitor. Thus, once H2Q is completely consumed, the inhibition is removed, and normal substrate turnover is initiated, which explains the lag phase. To probe the mechanism of lag phase, the reactions between H2Q and DHP were both studied both in the presence and in the absence of H2O2. The reversible reactions between ferric/oxyferrous DHP A and H2Q/1,4-BQ are shown to involve a proton-coupled electron transfer (PCET) mechanism, where the distal histidine His(55) serves as the proton acceptor. The pKa of the distal histidine His(55) has been determined by resonance Raman spectroscopy in order to corroborate its involvement in this mechanism. Consistent with the proposed mechanism, kinetic assays have shown that H2Q serves as a substrate for DHP that follows the Michaelis-Menten kinetics. Unlike H2Q, the product 1,4-BQ has a relatively large Ki value and therefore has negligible inhibition. This study sheds light on understanding the difference between substrate and inhibitor binding sites and regulatory implication for the peroxidase and oxygen-transporter functions in DHP. It also provides information on PCET in DHP, which is important for resolving the switching between the ferric peroxidase catalytic function and the ferrous oxygen transport function.}, number={47}, journal={JOURNAL OF PHYSICAL CHEMISTRY B}, author={Zhao, Jing and Zhao, Junjie and Franzen, Stefan}, year={2013}, month={Nov}, pages={14615–14624} }
 @article{zhao_de serrano_dumarieh_thompson_ghiladi_franzen_2012, title={The Role of the Distal Histidine in H2O2 Activation and Heme Protection in both Peroxidase and Globin Functions}, volume={116}, ISSN={1520-6106 1520-5207}, url={http://dx.doi.org/10.1021/jp300014b}, DOI={10.1021/jp300014b}, abstractNote={The distal histidine mutations of dehaloperoxidase-hemoglobin A (DHP A) to aspartate (H55D) and asparagine (H55N) have been prepared to study the role played by the distal histidine in both activation and protection against oxidation by radicals in heme proteins. The H55D and H55N mutants of DHP A have ~6-fold and ~11-fold lower peroxidase activities than wild type enzyme toward the oxidation of 2,4,6-trichlorophenol (TCP) to yield 2,6-dichloroquinone (DCQ) in the presence of H(2)O(2). The origin of the lower rate constants may be the solvent-exposed conformations of distal D55 and N55, which would have the dual effect of destabilizing the binding of H(2)O(2) to the heme iron, and of removing the acid-base catalyst necessary for the heterolytic O-O bond cleavage of heme-bound H(2)O(2) (i.e., compound 0). The partial peroxidase activity of H55D can be explained if one considers that there are two conformations of the distal aspartate (open and closed) by analogy with the distal histidine. We hypothesize that the distal aspartate has an active conformation in the distal pocket (closed). Although the open form is observed in the low-temperature X-ray crystal structure of ferric H55D, the closed form is observed in the FTIR spectrum of the carbonmonoxy form of the H55D mutant. Consistent with this model, the H55D mutant also shows inhibition of TCP oxidation by 4-bromophenol (4-BP). Consistent with the protection hypothesis, compound ES, the tyrosyl radical-containing ferryl intermediate observed in WT DHP A, was not observed in H55D.}, number={40}, journal={The Journal of Physical Chemistry B}, publisher={American Chemical Society (ACS)}, author={Zhao, Junjie and de Serrano, Vesna and Dumarieh, Rania and Thompson, Matt and Ghiladi, Reza A. and Franzen, Stefan}, year={2012}, month={Sep}, pages={12065–12077} }