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Full-Text Articles in Life Sciences

The Catalytic Mechanism Of Electron-Bifurcating Electron Transfer Flavoproteins (Etfs) Involves An Intermediary Complex With Nad+, Gerrit J. Schut, Nishya Mohamed-Raseek, Monika Tokmina-Lukaszewska, David W. Mulder, Diep M. N. Nguyen, Gina L. Lipscomb, John Patrick Hoben, Angela Patterson, Carolyn E. Lubner, Paul W. King, John W. Peters, Brian Bothner, Anne-Frances Miller, Michael W. W. Adams Dec 2018

The Catalytic Mechanism Of Electron-Bifurcating Electron Transfer Flavoproteins (Etfs) Involves An Intermediary Complex With Nad+, Gerrit J. Schut, Nishya Mohamed-Raseek, Monika Tokmina-Lukaszewska, David W. Mulder, Diep M. N. Nguyen, Gina L. Lipscomb, John Patrick Hoben, Angela Patterson, Carolyn E. Lubner, Paul W. King, John W. Peters, Brian Bothner, Anne-Frances Miller, Michael W. W. Adams

Chemistry Faculty Publications

Electron bifurcation plays a key role in anaerobic energy metabolism, but it is a relatively new discovery, and only limited mechanistic information is available on the diverse enzymes that employ it. Herein, we focused on the bifurcating electron transfer flavoprotein (ETF) from the hyperthermophilic archaeon Pyrobaculum aerophilum. The EtfABCX enzyme complex couples NADH oxidation to the endergonic reduction of ferredoxin and exergonic reduction of menaquinone. We developed a model for the enzyme structure by using nondenaturing MS, cross-linking, and homology modeling in which EtfA, -B, and -C each contained FAD, whereas EtfX contained two [4Fe-4S] clusters. On the basis …


Canvass: A Crowd-Sourced, Natural-Product Screening Library For Exploring Biological Space, Sara E. Kearney, Gergely ZahoráNszky-KőHalmi, Kyle R. Brimacombe, Mark J. Henderson, Caitlin Lynch, Tongan Zhao, Kanny K. Wan, Zina Itkin, Christopher Dillon, Min Shen, Dorian M. Cheff, Tobie D. Lee, Danielle Bougie, Ken Cheng, Nathan P. Coussens, Dorjbal Dorjsuren, Richard T. Eastman, Ruili Huang, Michael J. Iannotti, Surendra Karavadhi, Carleen Klumpp-Thomas, Jacob S. Roth, Srilatha Sakamuru, Wei Sun, Steven A. Titus, Adam Yasgar, Ya-Qin Zhang, Jinghua Zhao, Rodrigo B. Andrade, M. Kevin Brown, Robert B. Grossman Dec 2018

Canvass: A Crowd-Sourced, Natural-Product Screening Library For Exploring Biological Space, Sara E. Kearney, Gergely ZahoráNszky-KőHalmi, Kyle R. Brimacombe, Mark J. Henderson, Caitlin Lynch, Tongan Zhao, Kanny K. Wan, Zina Itkin, Christopher Dillon, Min Shen, Dorian M. Cheff, Tobie D. Lee, Danielle Bougie, Ken Cheng, Nathan P. Coussens, Dorjbal Dorjsuren, Richard T. Eastman, Ruili Huang, Michael J. Iannotti, Surendra Karavadhi, Carleen Klumpp-Thomas, Jacob S. Roth, Srilatha Sakamuru, Wei Sun, Steven A. Titus, Adam Yasgar, Ya-Qin Zhang, Jinghua Zhao, Rodrigo B. Andrade, M. Kevin Brown, Robert B. Grossman

Chemistry Faculty Publications

Natural products and their derivatives continue to be wellsprings of nascent therapeutic potential. However, many laboratories have limited resources for biological evaluation, leaving their previously isolated or synthesized compounds largely or completely untested. To address this issue, the Canvass library of natural products was assembled, in collaboration with academic and industry researchers, for quantitative high-throughput screening (qHTS) across a diverse set of cell-based and biochemical assays. Characterization of the library in terms of physicochemical properties, structural diversity, and similarity to compounds in publicly available libraries indicates that the Canvass library contains many structural elements in common with approved drugs. The …


Data On Spectrum-Based Fluorescence Resonance Energy Transfer Measurement Of E. Coli Multidrug Transporter Acrb, Yuguang Cai, Thomas E. Wilkop, Yinan Wei Dec 2018

Data On Spectrum-Based Fluorescence Resonance Energy Transfer Measurement Of E. Coli Multidrug Transporter Acrb, Yuguang Cai, Thomas E. Wilkop, Yinan Wei

Chemistry Faculty Publications

This paper presented the dataset of correction parameters used in the determination of the energy transfer efficiencies from the spectrum-based fluorescence resonance energy transfer (FRET) measurement in a trimeric membrane protein AcrB. The cyan fluorescent protein (CFP) and yellow fluorescent protein (YPet) were used as the donor and acceptor, respectively. Two AcrB fusion proteins were constructed, AcrB-CFP and AcrB-YPet. The proteins were co-expressed in Escherichia coli cells, and energy transfer efficiency were determined in live cells. To obtain reliable energy transfer data, a complete set of correction parameters need to be first determined to accommodate for factors such as background …


Cross Photoreaction Of Glyoxylic And Pyruvic Acids In Model Aqueous Aerosol, Sha-Sha Xia, Alexis J. Eugene, Marcelo I. Guzman Jul 2018

Cross Photoreaction Of Glyoxylic And Pyruvic Acids In Model Aqueous Aerosol, Sha-Sha Xia, Alexis J. Eugene, Marcelo I. Guzman

Chemistry Faculty Publications

Aerosols of variable composition, size, and shape are associated with public health concerns as well as with light-particle interactions that play a role in the energy balance of the atmosphere. Photochemical reactions of 2-oxocarboxylic acids in the aqueous phase are now known to contribute to the total secondary organic aerosol (SOA) budget. This work explores the cross reaction of glyoxylic acid (GA) and pyruvic acid (PA) in water, the two most abundant 2-oxocarboxylic acids in the atmosphere, under solar irradiation and dark thermal aging steps. During irradiation, PA and GA are excited and initiate proton-coupled electron transfer or hydrogen abstraction …


Role Of Protein Charge Density On Hepatitis B Virus Capsid Formation, Xinyu Sun, Dong Li, Zhaoshuai Wang, Panchao Yin, Rundong Hu, Rundong Hu, Hui Li, Qiao Liu, Yunyi Gao, Baiping Ren, Jie Zheng, Yinan Wei, Tianbo Liu Apr 2018

Role Of Protein Charge Density On Hepatitis B Virus Capsid Formation, Xinyu Sun, Dong Li, Zhaoshuai Wang, Panchao Yin, Rundong Hu, Rundong Hu, Hui Li, Qiao Liu, Yunyi Gao, Baiping Ren, Jie Zheng, Yinan Wei, Tianbo Liu

Chemistry Faculty Publications

The role of electrostatic interactions in the viral capsid assembly process was studied by comparing the assembly process of a truncated hepatitis B virus capsid protein Cp149 with its mutant protein D2N/D4N, which has the same conformational structure but four fewer charges per dimer. The capsid protein self-assembly was investigated under a wide range of protein surface charge densities by changing the protein concentration, buffer pH, and solution ionic strength. Lowering the protein charge density favored the capsid formation. However, lowering charge beyond a certain point resulted in capsid aggregation and precipitation. Interestingly, both the wild-type and D2N/D4N mutant displayed …


Distinct Properties Underlie Flavin-Based Electron Bifurcation In A Novel Electron Transfer Flavoprotein Fixab From Rhodopseudomonas Palustris, H. Diessel Duan, Carolyn E. Lubner, Monika Tokmina-Lukaszewska, George H. Gauss, Brian Bothner, Paul W. King, John W. Peters, Anne-Frances Miller Feb 2018

Distinct Properties Underlie Flavin-Based Electron Bifurcation In A Novel Electron Transfer Flavoprotein Fixab From Rhodopseudomonas Palustris, H. Diessel Duan, Carolyn E. Lubner, Monika Tokmina-Lukaszewska, George H. Gauss, Brian Bothner, Paul W. King, John W. Peters, Anne-Frances Miller

Chemistry Faculty Publications

A newly recognized third fundamental mechanism of energy conservation in biology, electron bifurcation, uses free energy from exergonic redox reactions to drive endergonic redox reactions. Flavin-based electron bifurcation furnishes low-potential electrons to demanding chemical reactions, such as reduction of dinitrogen to ammonia. We employed the heterodimeric flavoenzyme FixAB from the diazotrophic bacterium Rhodopseudomonas palustris to elucidate unique properties that underpin flavin-based electron bifurcation. FixAB is distinguished from canonical electron transfer flavoproteins (ETFs) by a second FAD that replaces the AMP of canonical ETF. We exploited near-UV–visible CD spectroscopy to resolve signals from the different flavin sites in FixAB and to …


Informing Efforts To Develop Nitroreductase For Amine Production, Anne-Frances Miller, Jonathan T. Park, Kyle L. Ferguson, Warintra Pitsawong, Andreas S. Bommarius Jan 2018

Informing Efforts To Develop Nitroreductase For Amine Production, Anne-Frances Miller, Jonathan T. Park, Kyle L. Ferguson, Warintra Pitsawong, Andreas S. Bommarius

Chemistry Faculty Publications

Nitroreductases (NRs) hold promise for converting nitroaromatics to aromatic amines. Nitroaromatic reduction rate increases with Hammett substituent constant for NRs from two different subgroups, confirming substrate identity as a key determinant of reactivity. Amine yields were low, but compounds yielding amines tend to have a large π system and electron withdrawing substituents. Therefore, we also assessed the prospects of varying the enzyme. Several different subgroups of NRs include members able to produce aromatic amines. Comparison of four NR subgroups shows that they provide contrasting substrate binding cavities with distinct constraints on substrate position relative to the flavin. The unique architecture …