1
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Boyd RJ, Olson TL, Zook JD, Stein D, Aceves M, Lin WH, Craciunescu FM, Hansen DT, Anastasiadis PZ, Singharoy A, Fromme P. Characterization and computational simulation of human Syx, a RhoGEF implicated in glioblastoma. FASEB J 2022; 36:e22378. [PMID: 35639414 PMCID: PMC9262375 DOI: 10.1096/fj.202101808rr] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Revised: 05/10/2022] [Accepted: 05/13/2022] [Indexed: 12/04/2022]
Abstract
Structural discovery of guanine nucleotide exchange factor (GEF) protein complexes is likely to become increasingly relevant with the development of new therapeutics targeting small GTPases and development of new classes of small molecules that inhibit protein‐protein interactions. Syx (also known as PLEKHG5 in humans) is a RhoA GEF implicated in the pathology of glioblastoma (GBM). Here we investigated protein expression and purification of ten different human Syx constructs and performed biophysical characterizations and computational studies that provide insights into why expression of this protein was previously intractable. We show that human Syx can be expressed and isolated and Syx is folded as observed by circular dichroism (CD) spectroscopy and actively binds to RhoA as determined by co‐elution during size exclusion chromatography (SEC). This characterization may provide critical insights into the expression and purification of other recalcitrant members of the large class of oncogenic—Diffuse B‐cell lymphoma (Dbl) homology GEF proteins. In addition, we performed detailed homology modeling and molecular dynamics simulations on the surface of a physiologically realistic membrane. These simulations reveal novel insights into GEF activity and allosteric modulation by the plekstrin homology (PH) domain. These newly revealed interactions between the GEF PH domain and the membrane embedded region of RhoA support previously unexplained experimental findings regarding the allosteric effects of the PH domain from numerous activity studies of Dbl homology GEF proteins. This work establishes new hypotheses for structural interactivity and allosteric signal modulation in Dbl homology RhoGEFs.
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Affiliation(s)
- Ryan J Boyd
- Biodesign Center for Applied Structural Discovery, Arizona State University, Tempe, Arizona, USA
| | - Tien L Olson
- Biodesign Center for Applied Structural Discovery, Arizona State University, Tempe, Arizona, USA
| | - James D Zook
- Biodesign Center for Applied Structural Discovery, Arizona State University, Tempe, Arizona, USA
| | - Derek Stein
- Biodesign Center for Applied Structural Discovery, Arizona State University, Tempe, Arizona, USA
| | - Manuel Aceves
- Biodesign Center for Applied Structural Discovery, Arizona State University, Tempe, Arizona, USA
| | - Wan-Hsin Lin
- Department of Cancer Biology, Mayo Clinic, Jacksonville, Florida, USA
| | - Felicia M Craciunescu
- Biodesign Center for Applied Structural Discovery, Arizona State University, Tempe, Arizona, USA
| | - Debra T Hansen
- Biodesign Center for Applied Structural Discovery, Arizona State University, Tempe, Arizona, USA.,Center for Innovations in Medicine, Arizona State University, Tempe, Arizona, USA
| | | | - Abhishek Singharoy
- Biodesign Center for Applied Structural Discovery, Arizona State University, Tempe, Arizona, USA
| | - Petra Fromme
- Biodesign Center for Applied Structural Discovery, Arizona State University, Tempe, Arizona, USA
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2
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Doppler D, Rabbani MT, Letrun R, Cruz Villarreal J, Kim DH, Gandhi S, Egatz-Gomez A, Sonker M, Chen J, Koua FHM, Yang J, Youssef M, Mazalova V, Bajt S, Shelby ML, Coleman MA, Wiedorn MO, Knoska J, Schön S, Sato T, Hunter MS, Hosseinizadeh A, Kuptiz C, Nazari R, Alvarez RC, Karpos K, Zaare S, Dobson Z, Discianno E, Zhang S, Zook JD, Bielecki J, de Wijn R, Round AR, Vagovic P, Kloos M, Vakili M, Ketawala GK, Stander NE, Olson TL, Morin K, Mondal J, Nguyen J, Meza-Aguilar JD, Kodis G, Vaiana S, Martin-Garcia JM, Mariani V, Schwander P, Schmidt M, Messerschmidt M, Ourmazd A, Zatsepin N, Weierstall U, Bruce BD, Mancuso AP, Grant T, Barty A, Chapman HN, Frank M, Fromme R, Spence JCH, Botha S, Fromme P, Kirian RA, Ros A. Co-flow injection for serial crystallography at X-ray free-electron lasers. J Appl Crystallogr 2022; 55:1-13. [PMID: 35153640 PMCID: PMC8805165 DOI: 10.1107/s1600576721011079] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Accepted: 10/22/2021] [Indexed: 02/03/2023] Open
Abstract
Serial femtosecond crystallography (SFX) is a powerful technique that exploits X-ray free-electron lasers to determine the structure of macro-molecules at room temperature. Despite the impressive exposition of structural details with this novel crystallographic approach, the methods currently available to introduce crystals into the path of the X-ray beam sometimes exhibit serious drawbacks. Samples requiring liquid injection of crystal slurries consume large quantities of crystals (at times up to a gram of protein per data set), may not be compatible with vacuum configurations on beamlines or provide a high background due to additional sheathing liquids present during the injection. Proposed and characterized here is the use of an immiscible inert oil phase to supplement the flow of sample in a hybrid microfluidic 3D-printed co-flow device. Co-flow generation is reported with sample and oil phases flowing in parallel, resulting in stable injection conditions for two different resin materials experimentally. A numerical model is presented that adequately predicts these flow-rate conditions. The co-flow generating devices reduce crystal clogging effects, have the potential to conserve protein crystal samples up to 95% and will allow degradation-free light-induced time-resolved SFX.
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Affiliation(s)
- Diandra Doppler
- School of Molecular Sciences, Arizona State University, Tempe, Arizona, USA,Center for Applied Structural Discovery, Biodesign Institute, Arizona State University, Tempe, Arizona, USA
| | - Mohammad T. Rabbani
- School of Molecular Sciences, Arizona State University, Tempe, Arizona, USA,Center for Applied Structural Discovery, Biodesign Institute, Arizona State University, Tempe, Arizona, USA
| | | | - Jorvani Cruz Villarreal
- School of Molecular Sciences, Arizona State University, Tempe, Arizona, USA,Center for Applied Structural Discovery, Biodesign Institute, Arizona State University, Tempe, Arizona, USA
| | - Dai Hyun Kim
- School of Molecular Sciences, Arizona State University, Tempe, Arizona, USA,Center for Applied Structural Discovery, Biodesign Institute, Arizona State University, Tempe, Arizona, USA
| | - Sahir Gandhi
- School of Molecular Sciences, Arizona State University, Tempe, Arizona, USA,Center for Applied Structural Discovery, Biodesign Institute, Arizona State University, Tempe, Arizona, USA
| | - Ana Egatz-Gomez
- School of Molecular Sciences, Arizona State University, Tempe, Arizona, USA,Center for Applied Structural Discovery, Biodesign Institute, Arizona State University, Tempe, Arizona, USA
| | - Mukul Sonker
- School of Molecular Sciences, Arizona State University, Tempe, Arizona, USA,Center for Applied Structural Discovery, Biodesign Institute, Arizona State University, Tempe, Arizona, USA
| | - Joe Chen
- Department of Physics, Arizona State University, Tempe, Arizona, USA
| | - Faisal H. M. Koua
- Center for Free-Electron Laser Science, Deutsches Elektronen-Synchrotron (DESY), Hamburg, Germany
| | - Jayhow Yang
- Center for Applied Structural Discovery, Biodesign Institute, Arizona State University, Tempe, Arizona, USA
| | - Mohamed Youssef
- Center for Free-Electron Laser Science, Deutsches Elektronen-Synchrotron (DESY), Hamburg, Germany
| | - Victoria Mazalova
- Center for Free-Electron Laser Science, Deutsches Elektronen-Synchrotron (DESY), Hamburg, Germany
| | - Saša Bajt
- Hamburg Center for Ultrafast Imaging, Hamburg, Germany,Deutsches Elektronen-Synchrotron (DESY), Hamburg, Germany
| | - Megan L. Shelby
- Lawrence Livermore National Laboratory (LLNL), Livermore, California, USA
| | - Matt A. Coleman
- Lawrence Livermore National Laboratory (LLNL), Livermore, California, USA
| | - Max O. Wiedorn
- Center for Free-Electron Laser Science, Deutsches Elektronen-Synchrotron (DESY), Hamburg, Germany,Hamburg Center for Ultrafast Imaging, Hamburg, Germany,Department of Physics, Universität Hamburg, Hamburg, Germany
| | - Juraj Knoska
- Center for Free-Electron Laser Science, Deutsches Elektronen-Synchrotron (DESY), Hamburg, Germany
| | - Silvan Schön
- Center for Free-Electron Laser Science, Deutsches Elektronen-Synchrotron (DESY), Hamburg, Germany
| | | | - Mark S. Hunter
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, California, USA
| | - Ahmad Hosseinizadeh
- Department of Physics, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin, USA
| | - Christopher Kuptiz
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, California, USA
| | - Reza Nazari
- Center for Applied Structural Discovery, Biodesign Institute, Arizona State University, Tempe, Arizona, USA,Department of Physics, Arizona State University, Tempe, Arizona, USA
| | - Roberto C. Alvarez
- Center for Applied Structural Discovery, Biodesign Institute, Arizona State University, Tempe, Arizona, USA,Department of Physics, Arizona State University, Tempe, Arizona, USA
| | - Konstantinos Karpos
- Center for Applied Structural Discovery, Biodesign Institute, Arizona State University, Tempe, Arizona, USA,Department of Physics, Arizona State University, Tempe, Arizona, USA
| | - Sahba Zaare
- Center for Applied Structural Discovery, Biodesign Institute, Arizona State University, Tempe, Arizona, USA,Department of Physics, Arizona State University, Tempe, Arizona, USA
| | - Zachary Dobson
- School of Molecular Sciences, Arizona State University, Tempe, Arizona, USA,Center for Applied Structural Discovery, Biodesign Institute, Arizona State University, Tempe, Arizona, USA
| | - Erin Discianno
- Center for Applied Structural Discovery, Biodesign Institute, Arizona State University, Tempe, Arizona, USA
| | - Shangji Zhang
- School of Molecular Sciences, Arizona State University, Tempe, Arizona, USA,Center for Applied Structural Discovery, Biodesign Institute, Arizona State University, Tempe, Arizona, USA
| | - James D. Zook
- School of Molecular Sciences, Arizona State University, Tempe, Arizona, USA,Center for Applied Structural Discovery, Biodesign Institute, Arizona State University, Tempe, Arizona, USA
| | | | | | - Adam R. Round
- European XFEL, Schenefeld, Germany,School of Chemical and Physical Sciences, Keele University, Staffordshire, UK
| | - Patrik Vagovic
- European XFEL, Schenefeld, Germany,Center for Free-Electron Laser Science, Deutsches Elektronen-Synchrotron (DESY), Hamburg, Germany
| | | | | | - Gihan K. Ketawala
- School of Molecular Sciences, Arizona State University, Tempe, Arizona, USA,Center for Applied Structural Discovery, Biodesign Institute, Arizona State University, Tempe, Arizona, USA
| | - Natasha E. Stander
- School of Molecular Sciences, Arizona State University, Tempe, Arizona, USA,Center for Applied Structural Discovery, Biodesign Institute, Arizona State University, Tempe, Arizona, USA
| | - Tien L. Olson
- School of Molecular Sciences, Arizona State University, Tempe, Arizona, USA,Center for Applied Structural Discovery, Biodesign Institute, Arizona State University, Tempe, Arizona, USA
| | - Katherine Morin
- Center for Applied Structural Discovery, Biodesign Institute, Arizona State University, Tempe, Arizona, USA
| | - Jyotirmory Mondal
- Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee, Knoxville, Tennessee, USA
| | - Jonathan Nguyen
- School of Molecular Sciences, Arizona State University, Tempe, Arizona, USA,Center for Applied Structural Discovery, Biodesign Institute, Arizona State University, Tempe, Arizona, USA
| | - José Domingo Meza-Aguilar
- Center for Applied Structural Discovery, Biodesign Institute, Arizona State University, Tempe, Arizona, USA,European XFEL, Schenefeld, Germany
| | - Gerdenis Kodis
- School of Molecular Sciences, Arizona State University, Tempe, Arizona, USA,Center for Applied Structural Discovery, Biodesign Institute, Arizona State University, Tempe, Arizona, USA,Department of Physics, Arizona State University, Tempe, Arizona, USA
| | - Sara Vaiana
- Department of Physics, Arizona State University, Tempe, Arizona, USA
| | - Jose M. Martin-Garcia
- Center for Applied Structural Discovery, Biodesign Institute, Arizona State University, Tempe, Arizona, USA,Department of Crystallography and Structural Biology, Institute of Physical Chemistry ‘Rocasolano’, CSIC, Madrid, Spain
| | - Valerio Mariani
- Center for Free-Electron Laser Science, Deutsches Elektronen-Synchrotron (DESY), Hamburg, Germany
| | - Peter Schwander
- Department of Physics, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin, USA
| | - Marius Schmidt
- Department of Physics, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin, USA
| | - Marc Messerschmidt
- School of Molecular Sciences, Arizona State University, Tempe, Arizona, USA,Center for Applied Structural Discovery, Biodesign Institute, Arizona State University, Tempe, Arizona, USA
| | - Abbas Ourmazd
- Department of Physics, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin, USA
| | - Nadia Zatsepin
- Center for Applied Structural Discovery, Biodesign Institute, Arizona State University, Tempe, Arizona, USA,Department of Physics, Arizona State University, Tempe, Arizona, USA,Department of Chemistry and Physics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Australia
| | - Uwe Weierstall
- Center for Applied Structural Discovery, Biodesign Institute, Arizona State University, Tempe, Arizona, USA,Department of Physics, Arizona State University, Tempe, Arizona, USA
| | - Barry D. Bruce
- Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee, Knoxville, Tennessee, USA
| | - Adrian P. Mancuso
- European XFEL, Schenefeld, Germany,Department of Chemistry and Physics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Australia
| | - Thomas Grant
- Department of Structural Biology, Jacobs School of Medicine and Biomedical Sciences, SUNY University at Buffalo, Buffalo, New York, USA
| | - Anton Barty
- Center for Free-Electron Laser Science, Deutsches Elektronen-Synchrotron (DESY), Hamburg, Germany,Deutsches Elektronen-Synchrotron (DESY), Hamburg, Germany,Center for Data and Computing in Natural Science CDCS, Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany
| | - Henry N. Chapman
- Center for Free-Electron Laser Science, Deutsches Elektronen-Synchrotron (DESY), Hamburg, Germany,Hamburg Center for Ultrafast Imaging, Hamburg, Germany,Department of Physics, Universität Hamburg, Hamburg, Germany
| | - Matthias Frank
- Lawrence Livermore National Laboratory (LLNL), Livermore, California, USA
| | - Raimund Fromme
- School of Molecular Sciences, Arizona State University, Tempe, Arizona, USA,Center for Applied Structural Discovery, Biodesign Institute, Arizona State University, Tempe, Arizona, USA
| | - John C. H. Spence
- Center for Applied Structural Discovery, Biodesign Institute, Arizona State University, Tempe, Arizona, USA,Department of Physics, Arizona State University, Tempe, Arizona, USA
| | - Sabine Botha
- Center for Applied Structural Discovery, Biodesign Institute, Arizona State University, Tempe, Arizona, USA,Department of Physics, Arizona State University, Tempe, Arizona, USA
| | - Petra Fromme
- School of Molecular Sciences, Arizona State University, Tempe, Arizona, USA,Center for Applied Structural Discovery, Biodesign Institute, Arizona State University, Tempe, Arizona, USA
| | - Richard A. Kirian
- Center for Applied Structural Discovery, Biodesign Institute, Arizona State University, Tempe, Arizona, USA,Department of Physics, Arizona State University, Tempe, Arizona, USA
| | - Alexandra Ros
- School of Molecular Sciences, Arizona State University, Tempe, Arizona, USA,Center for Applied Structural Discovery, Biodesign Institute, Arizona State University, Tempe, Arizona, USA,Correspondence e-mail:
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3
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Moran MW, Ramirez EP, Zook JD, Saarinen AM, Baravati B, Goode MR, Laloudakis V, Kaschner EK, Olson TL, Craciunescu FM, Hansen DT, Liu J, Fromme P. Biophysical characterization and a roadmap towards the NMR solution structure of G0S2, a key enzyme in non-alcoholic fatty liver disease. PLoS One 2021; 16:e0249164. [PMID: 34260600 PMCID: PMC8279337 DOI: 10.1371/journal.pone.0249164] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Accepted: 03/13/2021] [Indexed: 11/19/2022] Open
Abstract
In the United States non-alcoholic fatty liver disease (NAFLD) is the most common form of chronic liver disease, affecting an estimated 80 to 100 million people. It occurs in every age group, but predominantly in people with risk factors such as obesity and type 2 diabetes. NAFLD is marked by fat accumulation in the liver leading to liver inflammation, which may lead to scarring and irreversible damage progressing to cirrhosis and liver failure. In animal models, genetic ablation of the protein G0S2 leads to alleviation of liver damage and insulin resistance in high fat diets. The research presented in this paper aims to aid in rational based drug design for the treatment of NAFLD by providing a pathway for a solution state NMR structure of G0S2. Here we describe the expression of G0S2 in an E. coli system from two different constructs, both of which are confirmed to be functionally active based on the ability to inhibit the activity of Adipose Triglyceride Lipase. In one of the constructs, preliminary NMR spectroscopy measurements show dominant alpha-helical characteristics as well as resonance assignments on the N-terminus of G0S2, allowing for further NMR work with this protein. Additionally, the characterization of G0S2 oligomers are outlined for both constructs, suggesting that G0S2 may defensively exist in a multimeric state to protect and potentially stabilize the small 104 amino acid protein within the cell. This information presented on the structure of G0S2 will further guide future development in the therapy for NAFLD.
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Affiliation(s)
- Michael W. Moran
- Biodesign Center for Applied Structural Discovery, Arizona State University, Tempe, AZ, United States of America
- School of Molecular Sciences, Arizona State University, Tempe, AZ, United States of America
| | - Elizabeth P. Ramirez
- Biodesign Center for Applied Structural Discovery, Arizona State University, Tempe, AZ, United States of America
- School of Molecular Sciences, Arizona State University, Tempe, AZ, United States of America
| | - James D. Zook
- Biodesign Center for Applied Structural Discovery, Arizona State University, Tempe, AZ, United States of America
| | - Alicia M. Saarinen
- Department of Biochemistry and Molecular Biology, Mayo Clinic in Arizona Scottsdale, AZ, United States of America
- Department of Cardiovascular Medicine, Mayo Clinic in Arizona Scottsdale, AZ, United States of America
| | - Bobby Baravati
- Biodesign Center for Applied Structural Discovery, Arizona State University, Tempe, AZ, United States of America
- School of Molecular Sciences, Arizona State University, Tempe, AZ, United States of America
| | - Matthew R. Goode
- Biodesign Center for Applied Structural Discovery, Arizona State University, Tempe, AZ, United States of America
- School of Molecular Sciences, Arizona State University, Tempe, AZ, United States of America
| | - Vasiliki Laloudakis
- Biodesign Center for Applied Structural Discovery, Arizona State University, Tempe, AZ, United States of America
| | - Emily K. Kaschner
- Biodesign Center for Applied Structural Discovery, Arizona State University, Tempe, AZ, United States of America
- School of Molecular Sciences, Arizona State University, Tempe, AZ, United States of America
| | - Tien L. Olson
- Biodesign Center for Applied Structural Discovery, Arizona State University, Tempe, AZ, United States of America
- School of Molecular Sciences, Arizona State University, Tempe, AZ, United States of America
| | - Felicia M. Craciunescu
- Biodesign Center for Applied Structural Discovery, Arizona State University, Tempe, AZ, United States of America
| | - Debra T. Hansen
- Biodesign Center for Applied Structural Discovery, Arizona State University, Tempe, AZ, United States of America
- Biodesign Center for Innovations in Medicine, Arizona State University, Tempe, AZ, United States of America
| | - Jun Liu
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN, United States of America
| | - Petra Fromme
- Biodesign Center for Applied Structural Discovery, Arizona State University, Tempe, AZ, United States of America
- School of Molecular Sciences, Arizona State University, Tempe, AZ, United States of America
- * E-mail:
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4
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Olson TL, Zhang S, Labban D, Kaschner E, Aceves M, Iyer S, Meza-Aguilar JD, Zook JD, Chun E, Craciunescu FM, Liu W, Shi CX, Stewart AK, Hansen DT, Meurice N, Fromme P. Protein expression and purification of G-protein coupled receptor kinase 6 (GRK6), toward structure-based drug design and discovery for multiple myeloma. Protein Expr Purif 2021; 185:105890. [PMID: 33971243 DOI: 10.1016/j.pep.2021.105890] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Revised: 04/12/2021] [Accepted: 04/13/2021] [Indexed: 10/21/2022]
Abstract
Human G-protein coupled receptor kinase 6 (GRK6) belongs to the GRK4 kinase subfamily of the G protein-coupled receptor kinase family which comprises of GRK1, GRK2, and GRK4. These kinases phosphorylate ligand-activated G-protein coupled receptors (GPCRs), driving heterotrimeric G protein coupling, desensitization of GPCR, and β-arrestin recruitment. This reaction series mediates cellular signal pathways for cell survival, proliferation, migration and chemotaxis. GRK6 is a kinase target in multiple myeloma since it is highly expressed in myeloma cells compared to epithelial cells and has a significant role in mediating the chemotactic responses of T and B-lymphocytes. To support structure-based drug design, we describe three human GRK6 constructs, GRK6, GRK6His/EK, and GRK6His/TEV, designed for protein expression in Spodoptera frugiperda Sf9 insect cells. The first construct did not contain any purification tag whereas the other two constructs contained the His10 affinity tag, which increased purification yields. We report here that all three constructs of GRK6 were overexpressed in Sf9 insect cells and purified to homogeneity at levels that were suitable for co-crystallization of GRK6 with potential inhibitors. The yields of purified GRK6, GRK6His/EK, and GRK6His/TEV were 0.3 mg, 0.8 mg and 0.7 mg per liter of cell culture, respectively. In addition, we have shown that GRK6His/TEV with the His10 tag removed was highly homogeneous and monodisperse as observed by dynamic light scattering measurement and actively folded as exhibited by circular dichroism spectroscopy. The described methods will support the structure-based development of additional therapeutics against multiple myeloma.
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Affiliation(s)
- Tien L Olson
- Center for Applied Structural Discovery, Biodesign Institute at Arizona State University, Tempe, AZ, 85281, USA; School of Molecular Sciences, Arizona State University, Tempe, AZ, 85287, USA
| | - Shangji Zhang
- Center for Applied Structural Discovery, Biodesign Institute at Arizona State University, Tempe, AZ, 85281, USA; School of Molecular Sciences, Arizona State University, Tempe, AZ, 85287, USA
| | - Dillon Labban
- Center for Applied Structural Discovery, Biodesign Institute at Arizona State University, Tempe, AZ, 85281, USA; School of Molecular Sciences, Arizona State University, Tempe, AZ, 85287, USA
| | - Emily Kaschner
- Center for Applied Structural Discovery, Biodesign Institute at Arizona State University, Tempe, AZ, 85281, USA; School of Molecular Sciences, Arizona State University, Tempe, AZ, 85287, USA
| | - Manuel Aceves
- Center for Applied Structural Discovery, Biodesign Institute at Arizona State University, Tempe, AZ, 85281, USA; School of Molecular Sciences, Arizona State University, Tempe, AZ, 85287, USA
| | - Srivatsan Iyer
- Center for Applied Structural Discovery, Biodesign Institute at Arizona State University, Tempe, AZ, 85281, USA; School of Molecular Sciences, Arizona State University, Tempe, AZ, 85287, USA
| | - Jose Domingo Meza-Aguilar
- Center for Applied Structural Discovery, Biodesign Institute at Arizona State University, Tempe, AZ, 85281, USA
| | - James D Zook
- Center for Applied Structural Discovery, Biodesign Institute at Arizona State University, Tempe, AZ, 85281, USA
| | - Eugene Chun
- Center for Applied Structural Discovery, Biodesign Institute at Arizona State University, Tempe, AZ, 85281, USA
| | - Felicia M Craciunescu
- Center for Applied Structural Discovery, Biodesign Institute at Arizona State University, Tempe, AZ, 85281, USA
| | - Wei Liu
- Center for Applied Structural Discovery, Biodesign Institute at Arizona State University, Tempe, AZ, 85281, USA; School of Molecular Sciences, Arizona State University, Tempe, AZ, 85287, USA
| | - Chang-Xin Shi
- Department of Hematology/Oncology, Mayo Clinic, Scottsdale, AZ, 85289, USA; Precision Cancer Therapeutics, Center for Individualized Medicine, Mayo Clinic, Scottsdale, AZ, 85289, USA
| | - A Keith Stewart
- Department of Hematology/Oncology, Mayo Clinic, Scottsdale, AZ, 85289, USA; Precision Cancer Therapeutics, Center for Individualized Medicine, Mayo Clinic, Scottsdale, AZ, 85289, USA
| | - Debra T Hansen
- Center for Applied Structural Discovery, Biodesign Institute at Arizona State University, Tempe, AZ, 85281, USA; Center for Innovations in Medicine, Biodesign Institute at Arizona State University, Tempe, AZ, 85281, USA
| | - Nathalie Meurice
- Department of Hematology/Oncology, Mayo Clinic, Scottsdale, AZ, 85289, USA; Precision Cancer Therapeutics, Center for Individualized Medicine, Mayo Clinic, Scottsdale, AZ, 85289, USA
| | - Petra Fromme
- Center for Applied Structural Discovery, Biodesign Institute at Arizona State University, Tempe, AZ, 85281, USA; School of Molecular Sciences, Arizona State University, Tempe, AZ, 85287, USA.
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5
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Guo Q, Yaron JR, Wallen JW, Browder KF, Boyd R, Olson TL, Burgin M, Ulrich P, Aliskevich E, Schutz LN, Fromme P, Zhang L, Lucas AR. PEGylated Serp-1 Markedly Reduces Pristane-Induced Experimental Diffuse Alveolar Hemorrhage, Altering uPAR Distribution, and Macrophage Invasion. Front Cardiovasc Med 2021; 8:633212. [PMID: 33665212 PMCID: PMC7921738 DOI: 10.3389/fcvm.2021.633212] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Accepted: 01/20/2021] [Indexed: 12/22/2022] Open
Abstract
Diffuse alveolar hemorrhage (DAH) is one of the most serious clinical complications of systemic lupus erythematosus (SLE). The prevalence of DAH is reported to range from 1 to 5%, but while DAH is considered a rare complication there is a reported 50-80% mortality. There is at present no proven effective treatment for DAH and the therapeutics that have been tested have significant side effects. There is a clear necessity to discover new drugs to improve outcomes in DAH. Serine protease inhibitors, serpins, regulate thrombotic and thrombolytic protease cascades. We are investigating a Myxomavirus derived immune modulating serpin, Serp-1, as a new class of immune modulating therapeutics for vasculopathy and lung hemorrhage. Serp-1 has proven efficacy in models of herpes virus-induced arterial inflammation (vasculitis) and lung hemorrhage and has also proved safe in a clinical trial in patients with unstable coronary syndromes and stent implant. Here, we examine Serp-1, both as a native secreted protein expressed by CHO cells and as a polyethylene glycol modified (PEGylated) variant (Serp-1m5), for potential therapy in DAH. DAH was induced by intraperitoneal (IP) injection of pristane in C57BL/6J (B6) mice. Mice were treated with 100 ng/g bodyweight of either Serp-1 as native 55 kDa secreted glycoprotein, or as Serp-1m5, or saline controls after inducing DAH. Treatments were repeated daily for 14 days (6 mice/group). Serp-1 partially and Serp-1m5 significantly reduced pristane-induced DAH when compared with saline as assessed by gross pathology and H&E staining (Serp-1, p = 0.2172; Serp-1m5, p = 0.0252). Both Serp-1m5 and Serp-1 treatment reduced perivascular inflammation and reduced M1 macrophage (Serp-1, p = 0.0350; Serp-1m5, p = 0.0053), hemosiderin-laden macrophage (Serp-1, p = 0.0370; Serp-1m5, p = 0.0424) invasion, and complement C5b/9 staining. Extracellular urokinase-type plasminogen activator receptor positive (uPAR+) clusters were significantly reduced (Serp-1, p = 0.0172; Serp-1m5, p = 0.0025). Serp-1m5 also increased intact uPAR+ alveoli in the lung (p = 0.0091). In conclusion, Serp-1m5 significantly reduces lung damage and hemorrhage in a pristane model of SLE DAH, providing a new potential therapeutic approach.
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Affiliation(s)
- Qiuyun Guo
- Center for Personalized Diagnostics and Center for Immunotherapy, Vaccines and Virotherapy, The Biodesign Institute, Arizona State University, Tempe, AZ, United States.,Department of Oncology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Jordan R Yaron
- Center for Personalized Diagnostics and Center for Immunotherapy, Vaccines and Virotherapy, The Biodesign Institute, Arizona State University, Tempe, AZ, United States
| | - John W Wallen
- Exalt Therapeutics LLC, Las Vegas, NV, United States
| | - Kyle F Browder
- Center for Personalized Diagnostics and Center for Immunotherapy, Vaccines and Virotherapy, The Biodesign Institute, Arizona State University, Tempe, AZ, United States
| | - Ryan Boyd
- Center for Applied Structural Discovery, The Biodesign Institute, Arizona State University, Tempe, AZ, United States
| | - Tien L Olson
- Center for Applied Structural Discovery, The Biodesign Institute, Arizona State University, Tempe, AZ, United States
| | - Michelle Burgin
- Center for Personalized Diagnostics and Center for Immunotherapy, Vaccines and Virotherapy, The Biodesign Institute, Arizona State University, Tempe, AZ, United States
| | - Peaches Ulrich
- Center for Personalized Diagnostics and Center for Immunotherapy, Vaccines and Virotherapy, The Biodesign Institute, Arizona State University, Tempe, AZ, United States
| | - Emily Aliskevich
- Center for Personalized Diagnostics and Center for Immunotherapy, Vaccines and Virotherapy, The Biodesign Institute, Arizona State University, Tempe, AZ, United States
| | - Lauren N Schutz
- Center for Personalized Diagnostics and Center for Immunotherapy, Vaccines and Virotherapy, The Biodesign Institute, Arizona State University, Tempe, AZ, United States
| | - Petra Fromme
- Center for Applied Structural Discovery, The Biodesign Institute, Arizona State University, Tempe, AZ, United States
| | - Liqiang Zhang
- Center for Personalized Diagnostics and Center for Immunotherapy, Vaccines and Virotherapy, The Biodesign Institute, Arizona State University, Tempe, AZ, United States
| | - Alexandra R Lucas
- Center for Personalized Diagnostics and Center for Immunotherapy, Vaccines and Virotherapy, The Biodesign Institute, Arizona State University, Tempe, AZ, United States
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6
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Olson TL, O'Neil ER, Ramanathan K, Lorusso R, MacLaren G, Anders MM. Extracorporeal membrane oxygenation in peripartum cardiomyopathy: A review of the ELSO Registry. Int J Cardiol 2020; 311:71-76. [PMID: 32321653 DOI: 10.1016/j.ijcard.2020.03.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Revised: 02/23/2020] [Accepted: 03/02/2020] [Indexed: 10/24/2022]
Abstract
AIMS Data on the use of extracorporeal membrane oxygenation (ECMO) for cardiogenic shock in peripartum cardiomyopathy (PPCM) is limited. We queried the Extracorporeal Life Support Organization (ELSO) Registry for PPCM patients treated with ECMO in order to characterize demographic and clinical features, complications, survival, and variables associated with mortality. METHODS AND RESULTS This was a retrospective review of patients voluntarily entered into the ELSO Registry. De-identified data was collected on patients with a diagnosis of PPCM based on ICD-9/ICD-10 coding who received ECMO between 2007 and 2019. Collected data included demographics, ECMO mode, cannulation strategies, pre-ECMO ventilator, biochemical, and hemodynamic parameters, run duration, complications, and survival to wean off ECMO and hospital discharge. Our primary outcome measure was survival to discharge. In the final analysis, 88 veno-arterial (VA) ECMO patients were included. Overall, 72% of patients were weaned off ECMO, including 10% who were weaned to ventricular assist device or heart transplantation, and 64% survived to hospital discharge. Extracorporeal cardiopulmonary resuscitation (ECPR) was performed in 11% of patients with 60% survival. Factors associated with decreased survival included neurologic complications (p = 0.03), specifically central nervous system hemorrhage (p = 0.01). CONCLUSION Our review is the largest to date of PPCM patients supported with VA ECMO for cardiogenic shock. ECMO and ECPR are valuable forms of short-term mechanical circulatory support with acceptable mortality profiles for PPCM patients who remain refractory to aggressive medical management. Complications should be meticulously avoided, especially neurologic complications.
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Affiliation(s)
- T L Olson
- Department of Pediatrics, Baylor College of Medicine, Houston, TX, USA.
| | - E R O'Neil
- Department of Pediatrics, Baylor College of Medicine, Houston, TX, USA
| | - K Ramanathan
- Cardiothoracic Intensive Care Unit, National University Hospital, Singapore
| | - R Lorusso
- Cardio-Thoracic Department, Heart and Vascular Centre, Maastricht University Medical Centre, Cardiovascular Research Institute Maastricht (CARIM), Maastricht, the Netherlands
| | - G MacLaren
- Paediatric Intensive Care Unit, Royal Children's Hospital, University of Melbourne, Melbourne, Australia
| | - M M Anders
- Section of Critical Care Medicine, Department of Pediatrics, Baylor College of Medicine, Texas Children's Hospital, Houston, TX, USA
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7
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Espiritu E, Olson TL, Williams JC, Allen JP. Binding and Energetics of Electron Transfer between an Artificial Four-Helix Mn-Protein and Reaction Centers from Rhodobacter sphaeroides. Biochemistry 2017; 56:6460-6469. [PMID: 29131579 DOI: 10.1021/acs.biochem.7b00978] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The ability of an artificial four-helix bundle Mn-protein, P1, to bind and transfer an electron to photosynthetic reaction centers from the purple bacterium Rhodobacter sphaeroides was characterized using optical spectroscopy. Upon illumination of reaction centers, an electron is transferred from P, the bacteriochlorophyll dimer, to QA, the primary electron acceptor. The P1 Mn-protein can bind to the reaction center and reduce the oxidized bacteriochlorophyll dimer, P+, with a dissociation constant of 1.2 μM at pH 9.4, comparable to the binding constant of c-type cytochromes. Amino acid substitutions of surface residues on the Mn-protein resulted in increases in the dissociation constant to 8.3 μM. The extent of reduction of P+ by the P1 Mn-protein was dependent on the P/P+ midpoint potential and the pH. Analysis of the free energy difference yielded a midpoint potential of approximately 635 mV at pH 9.4 for the Mn cofactor of the P1 Mn-protein, a value similar to those found for other Mn cofactors in proteins. The linear dependence of -56 mV/pH is consistent with one proton being released upon Mn oxidation, allowing the complex to maintain overall charge neutrality. These outcomes demonstrate the feasibility of designing four-helix bundles and other artificial metalloproteins to bind and transfer electrons to bacterial reaction centers and establish the usefulness of this system as a platform for designing sites to bind novel metal cofactors capable of performing complex oxidation-reduction reactions.
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Affiliation(s)
- Eduardo Espiritu
- School of Molecular Sciences, Arizona State University , Tempe, Arizona 85287-1604, United States
| | - Tien L Olson
- School of Molecular Sciences, Arizona State University , Tempe, Arizona 85287-1604, United States
| | - JoAnn C Williams
- School of Molecular Sciences, Arizona State University , Tempe, Arizona 85287-1604, United States
| | - James P Allen
- School of Molecular Sciences, Arizona State University , Tempe, Arizona 85287-1604, United States
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8
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Olson TL, Espiritu E, Edwardraja S, Canarie E, Flores M, Williams JC, Ghirlanda G, Allen JP. Biochemical and spectroscopic characterization of dinuclear Mn-sites in artificial four-helix bundle proteins. Biochim Biophys Acta Bioenerg 2017; 1858:945-954. [PMID: 28882760 DOI: 10.1016/j.bbabio.2017.08.013] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2017] [Revised: 08/28/2017] [Accepted: 08/31/2017] [Indexed: 01/18/2023]
Abstract
To better understand metalloproteins with Mn-clusters, we have designed artificial four-helix bundles to have one, two, or three dinuclear metal centers able to bind Mn(II). Circular dichroism measurements showed that the Mn-proteins have substantial α-helix content, and analysis of electron paramagnetic resonance spectra is consistent with the designed number of bound Mn-clusters. The Mn-proteins were shown to catalyze the conversion of hydrogen peroxide into molecular oxygen. The loss of hydrogen peroxide was dependent upon the concentration of protein with bound Mn, with the proteins containing multiple Mn-clusters showing greater activity. Using an oxygen sensor, the oxygen concentration was found to increase with a rate up to 0.4μM/min, which was dependent upon the concentrations of hydrogen peroxide and the Mn-protein. In addition, the Mn-proteins were shown to serve as electron donors to bacterial reaction centers using optical spectroscopy. Similar binding of the Mn-proteins to reaction centers was observed with an average dissociation constant of 2.3μM. The Mn-proteins with three metal centers were more effective at this electron transfer reaction than the Mn-proteins with one or two metal centers. Thus, multiple Mn-clusters can be incorporated into four-helix bundles with the capability of performing catalysis and electron transfer to a natural protein.
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Affiliation(s)
- Tien L Olson
- School of Molecular Sciences, Arizona State University, Tempe, AZ 85287-1604, USA
| | - Eduardo Espiritu
- School of Molecular Sciences, Arizona State University, Tempe, AZ 85287-1604, USA
| | | | - Elizabeth Canarie
- School of Molecular Sciences, Arizona State University, Tempe, AZ 85287-1604, USA
| | - Marco Flores
- School of Molecular Sciences, Arizona State University, Tempe, AZ 85287-1604, USA
| | - JoAnn C Williams
- School of Molecular Sciences, Arizona State University, Tempe, AZ 85287-1604, USA
| | - Giovanna Ghirlanda
- School of Molecular Sciences, Arizona State University, Tempe, AZ 85287-1604, USA
| | - James P Allen
- School of Molecular Sciences, Arizona State University, Tempe, AZ 85287-1604, USA.
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9
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Olson TL, Espiritu E, Edwardraja S, Simmons CR, Williams JC, Ghirlanda G, Allen JP. Design of dinuclear manganese cofactors for bacterial reaction centers. Biochim Biophys Acta 2015; 1857:539-547. [PMID: 26392146 DOI: 10.1016/j.bbabio.2015.09.003] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2015] [Accepted: 09/14/2015] [Indexed: 12/28/2022]
Abstract
A compelling target for the design of electron transfer proteins with novel cofactors is to create a model for the oxygen-evolving complex, a Mn4Ca cluster, of photosystem II. A mononuclear Mn cofactor can be added to the bacterial reaction center, but the addition of multiple metal centers is constrained by the native protein architecture. Alternatively, metal centers can be incorporated into artificial proteins. Designs for the addition of dinuclear metal centers to four-helix bundles resulted in three artificial proteins with ligands for one, two, or three dinuclear metal centers able to bind Mn. The three-dimensional structure determined by X-ray crystallography of one of the Mn-proteins confirmed the design features and revealed details concerning coordination of the Mn center. Electron transfer between these artificial Mn-proteins and bacterial reaction centers was investigated using optical spectroscopy. After formation of a light-induced, charge-separated state, the experiments showed that the Mn-proteins can donate an electron to the oxidized bacteriochlorophyll dimer of modified reaction centers, with the Mn-proteins having additional metal centers being more effective at this electron transfer reaction. Modeling of the structure of the Mn-protein docked to the reaction center showed that the artificial protein likely binds on the periplasmic surface similarly to cytochrome c2, the natural secondary donor. Combining reaction centers with exogenous artificial proteins provides the opportunity to create ligands and investigate the influence of inhomogeneous protein environments on multinuclear redox-active metal centers. This article is part of a Special Issue entitled Biodesign for Bioenergetics--the design and engineering of electronic transfer cofactors, proteins and protein networks, edited by Ronald L. Koder and J.L. Ross Anderson.
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Affiliation(s)
- Tien L Olson
- School of Molecular Sciences, Arizona State University, Tempe, AZ 85287-1604, USA
| | - Eduardo Espiritu
- School of Molecular Sciences, Arizona State University, Tempe, AZ 85287-1604, USA
| | | | - Chad R Simmons
- School of Molecular Sciences, Arizona State University, Tempe, AZ 85287-1604, USA
| | - JoAnn C Williams
- School of Molecular Sciences, Arizona State University, Tempe, AZ 85287-1604, USA
| | - Giovanna Ghirlanda
- School of Molecular Sciences, Arizona State University, Tempe, AZ 85287-1604, USA
| | - James P Allen
- School of Molecular Sciences, Arizona State University, Tempe, AZ 85287-1604, USA.
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10
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Flores M, Olson TL, Wang D, Edwardraja S, Shinde S, Williams JC, Ghirlanda G, Allen JP. Copper Environment in Artificial Metalloproteins Probed by Electron Paramagnetic Resonance Spectroscopy. J Phys Chem B 2015. [DOI: 10.1021/acs.jpcb.5b04172] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Affiliation(s)
- Marco Flores
- Department
of Chemistry and
Biochemistry, Arizona State University, Tempe, Arizona 85287-1604, United States
| | - Tien L. Olson
- Department
of Chemistry and
Biochemistry, Arizona State University, Tempe, Arizona 85287-1604, United States
| | - Dong Wang
- Department
of Chemistry and
Biochemistry, Arizona State University, Tempe, Arizona 85287-1604, United States
| | - Selvakumar Edwardraja
- Department
of Chemistry and
Biochemistry, Arizona State University, Tempe, Arizona 85287-1604, United States
| | - Sandip Shinde
- Department
of Chemistry and
Biochemistry, Arizona State University, Tempe, Arizona 85287-1604, United States
| | - JoAnn C. Williams
- Department
of Chemistry and
Biochemistry, Arizona State University, Tempe, Arizona 85287-1604, United States
| | - Giovanna Ghirlanda
- Department
of Chemistry and
Biochemistry, Arizona State University, Tempe, Arizona 85287-1604, United States
| | - James P. Allen
- Department
of Chemistry and
Biochemistry, Arizona State University, Tempe, Arizona 85287-1604, United States
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11
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Olson TL, Williams JC, Allen JP. The three-dimensional structures of bacterial reaction centers. Photosynth Res 2014; 120:87-98. [PMID: 23575738 DOI: 10.1007/s11120-013-9821-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/06/2013] [Accepted: 03/27/2013] [Indexed: 06/02/2023]
Abstract
This review presents a broad overview of the research that enabled the structure determination of the bacterial reaction centers from Blastochloris viridis and Rhodobacter sphaeroides, with a focus on the contributions from Duysens, Clayton, and Feher. Early experiments performed in the laboratory of Duysens and others demonstrated the utility of spectroscopic techniques and the presence of photosynthetic complexes in both oxygenic and anoxygenic photosynthesis. The laboratories of Clayton and Feher led efforts to isolate and characterize the bacterial reaction centers. The availability of well-characterized preparations of pure and stable reaction centers allowed the crystallization and subsequent determination of the structures using X-ray diffraction. The three-dimensional structures of reaction centers revealed an overall arrangement of two symmetrical branches of cofactors surrounded by transmembrane helices from the L and M subunits, which also are related by the same twofold symmetry axis. The structure has served as a framework to address several issues concerning bacterial photosynthesis, including the directionality of electron transfer, the properties of the reaction center-cytochrome c 2 complex, and the coupling of proton and electron transfer. Together, these research efforts laid the foundation for ongoing efforts to address an outstanding question in oxygenic photosynthesis, namely the molecular mechanism of water oxidation.
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Affiliation(s)
- T L Olson
- Department of Chemistry and Biochemistry, Arizona State University, Tempe, AZ, 85287-1604, USA
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12
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Tufts AA, Flores M, Olson TL, Williams JC, Allen JP. Electronic structure of the Mn-cofactor of modified bacterial reaction centers measured by electron paramagnetic resonance and electron spin echo envelope modulation spectroscopies. Photosynth Res 2014; 120:207-220. [PMID: 23868400 DOI: 10.1007/s11120-013-9887-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2013] [Accepted: 07/06/2013] [Indexed: 06/02/2023]
Abstract
The electronic structure of a Mn(II) ion bound to highly oxidizing reaction centers of Rhodobacter sphaeroides was studied in a mutant modified to possess a metal binding site at a location comparable to the Mn4Ca cluster of photosystem II. The Mn-binding site of the previously described mutant, M2, contains three carboxylates and one His at the binding site (Thielges et al., Biochemistry 44:389-7394, 2005). The redox-active Mn-cofactor was characterized using electron paramagnetic resonance (EPR) and electron spin echo envelope modulation (ESEEM) spectroscopies. In the light without bound metal, the Mn-binding mutants showed an EPR spectrum characteristic of the oxidized bacteriochlorophyll dimer and reduced quinone whose intensity was significantly reduced due to the diminished quantum yield of charge separation in the mutant compared to wild type. In the presence of the metal and in the dark, the EPR spectrum measured at the X-band frequency of 9.4 GHz showed a distinctive spin 5/2 Mn(II) signal consisting of 16 lines associated with both allowed and forbidden transitions. Upon illumination, the amplitude of the spectrum is decreased by over 80 % due to oxidation of the metal upon electron transfer to the oxidized bacteriochlorophyll dimer. The EPR spectrum of the Mn-cofactor was also measured at the Q-band frequency of 34 GHz and was better resolved as the signal was composed of the six allowed electronic transitions with only minor contributions from other transitions. A fit of the Q-band EPR spectrum shows that the Mn-cofactor is a high spin Mn(II) species (S = 5/2) that is six-coordinated with an isotropic g-value of 2.0006, a weak zero-field splitting and E/D ratio of approximately 1/3. The ESEEM experiments showed the presence of one (14)N coordinating the Mn-cofactor. The nitrogen atom is assigned to a His by comparing our ESEEM results to those previously reported for Mn(II) ions bound to other proteins and on the basis of the X-ray structure of the M2 mutant that shows the presence of only one His, residue M193, that can coordinate the Mn-cofactor. Together, the data allow the electronic structure and coordination environment of the designed Mn-cofactor in the modified reaction centers to be characterized in detail and compared to those observed in other proteins with Mn-cofactors.
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Affiliation(s)
- A A Tufts
- Department of Chemistry and Biochemistry, Arizona State University, Tempe, AZ, 85287-1604, USA
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13
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Kuang L, Olson TL, Lin S, Flores M, Jiang Y, Zheng W, Williams JC, Allen JP, Liang H. Interface for Light-Driven Electron Transfer by Photosynthetic Complexes Across Block Copolymer Membranes. J Phys Chem Lett 2014; 5:787-791. [PMID: 26274068 DOI: 10.1021/jz402766y] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Incorporation of membrane proteins into nanodevices to mediate recognition and transport in a collective and scalable fashion remains a challenging problem. We demonstrate how nanoscale photovoltaics could be designed using robust synthetic nanomembranes with incorporated photosynthetic reaction centers (RCs). Specifically, RCs from Rhodobacter sphaeroides are reconstituted spontaneously into rationally designed polybutadiene membranes to form hierarchically organized proteopolymer membrane arrays via a charge-interaction-directed reconstitution mechanism. Once incorporated, the RCs are fully active for prolonged periods based upon a variety of spectroscopic measurements, underscoring preservation of their 3D pigment configuration critical for light-driven charge transfer. This result provides a strategy to construct solar conversion devices using structurally versatile proteopolymer membranes with integrated RC functions to harvest broad regions of the solar spectrum.
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Affiliation(s)
- Liangju Kuang
- †Department of Metallurgical and Materials Engineering, Colorado School of Mines, Golden, Colorado 80401, United States
| | - Tien L Olson
- ‡Department of Chemistry and Biochemistry, Arizona State University, Tempe, Arizona 85287, United States
| | - Su Lin
- ‡Department of Chemistry and Biochemistry, Arizona State University, Tempe, Arizona 85287, United States
| | - Marco Flores
- ‡Department of Chemistry and Biochemistry, Arizona State University, Tempe, Arizona 85287, United States
| | - Yunjiang Jiang
- †Department of Metallurgical and Materials Engineering, Colorado School of Mines, Golden, Colorado 80401, United States
| | - Wan Zheng
- †Department of Metallurgical and Materials Engineering, Colorado School of Mines, Golden, Colorado 80401, United States
| | - JoAnn C Williams
- ‡Department of Chemistry and Biochemistry, Arizona State University, Tempe, Arizona 85287, United States
| | - James P Allen
- ‡Department of Chemistry and Biochemistry, Arizona State University, Tempe, Arizona 85287, United States
| | - Hongjun Liang
- †Department of Metallurgical and Materials Engineering, Colorado School of Mines, Golden, Colorado 80401, United States
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Olson TL, Williams JC, Allen JP. Influence of protein interactions on oxidation/reduction midpoint potentials of cofactors in natural and de novo metalloproteins. Biochim Biophys Acta 2013; 1827:914-22. [PMID: 23466333 DOI: 10.1016/j.bbabio.2013.02.014] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2012] [Revised: 02/13/2013] [Accepted: 02/23/2013] [Indexed: 01/14/2023]
Abstract
As discussed throughout this special issue, oxidation and reduction reactions play critical roles in the function of many organisms. In photosynthetic organisms, the conversion of light energy drives oxidation and reduction reactions through the transfer of electrons and protons in order to create energy-rich compounds. These reactions occur in proteins such as cytochrome c, a heme-containing water-soluble protein, the bacteriochlorophyll-containing reaction center, and photosystem II where water is oxidized at the manganese cluster. A critical measure describing the ability of cofactors in proteins to participate in such reactions is the oxidation/reduction midpoint potential. In this review, the basic concepts of oxidation/reduction reactions are reviewed with a summary of the experimental approaches used to measure the midpoint potential of metal cofactors. For cofactors in proteins, the midpoint potential not only depends upon the specific chemical characteristics of cofactors but also upon interactions with the surrounding protein, such as the nature of the coordinating ligands and protein environment. These interactions can be tailored to optimize an oxidation/reduction reaction carried out by the protein. As examples, the midpoint potentials of hemes in cytochromes, bacteriochlorophylls in reaction centers, and the manganese cluster of photosystem II are discussed with an emphasis on the influence that protein interactions have on these potentials. This article is part of a Special Issue entitled: Metals in Bioenergetics and Biomimetics Systems.
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Affiliation(s)
- T L Olson
- Department of Chemistry and Biochemistry, Arizona State University, Tempe, AZ 85287-1604, USA
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15
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Olson TL, Downey VW. Infant physiological responses to noxious stimuli of circumcision with anesthesia and analgesia. Pediatr Nurs 1998; 24:385-9. [PMID: 9849273] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
PURPOSE To compare the efficacy of dorsal penile nerve block (DPNB) and eutectic mixture of local anesthetic (EMLA) for attenuation of neonatal pain during circumcision. METHOD A total of 20 infants born at a United States upper Midwestern hospital were involved in the study. Measurements of blood pressure, heart rate, respiratory rate, and oxygen saturation were obtained along with a Neonatal Infant Pain Scale (NIPS) grading at five separate intervals (baseline, restraint, incision, Gomco clamp application, and post circumcision) throughout the circumcision procedure. A comparison was done between the two groups regarding response to the noxious stimuli. FINDINGS Infants demonstrate physiological and behavioral response to pain. These physiological and behavioral responses are observable and measurable. In addition, results show less response with the DPNB as compared to the EMLA. CONCLUSIONS There is a trend toward better pain control with the DPNB as compared to EMLA.
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Affiliation(s)
- T L Olson
- Anesthesia Associates, Fargo, ND, USA
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16
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Abstract
We have investigated the role of glycosylation on the post-translational processing of the insulin, and EGF proreceptor polypeptides. Following translation of the insulin proreceptor, by 3T3-L1 adipocytes, about 1.5 h are required for its conversion into active receptor; an additional 1.5 h are needed for the active receptor to reach the plasma membrane. During this 3-hour period the proreceptor undergoes a complex series of processing events, glycosylation being an essential processing step. Thus, treatment of 3T3-L1 adipocytes with tunicamycin caused the loss of cellular insulin binding activity and the accumulation of an inactive aglyco-proreceptor. Similarly, it was demonstrated in human A431 epidermoid carcinoma cells that the initial EGF-proreceptor (160 kDa) translation product undergoes a slow (t 1/2 = 30 min) processing step by which ligand (EGF) binding activity was acquired. It was shown that N-linked core oligosaccharide addition is essential for this critical processing step and the acquisition of EGF binding activity. This was found not to require the conversion of high mannose chains to complex chains which have been capped with fucose and sialic acid. Possible explanations for this activation in terms of translocation of intermediates and/or formation of disulfide bonds are discussed. To investigate post-translational processing of normal insulin proreceptor and the role of glycosylation in active receptor formation, metabolic labeling experiments were conducted. The first 35S-methionine-labeled intermediate detected is a 190 kDa polypeptide (proreceptor) which is rapidly (t 1/2 = 15 min) processed into a 210 kDa species. Both polypeptides contain N-linked core oligosaccharide chains, but in the latter case these chains appear to contain terminal N-acetylglucosamine. The 210 kDa precursor is converted slowly (t 1/2 = 2 h) by proteolytic processing into a 125 kDa (alpha') and 83 kDa (beta') species. Immediately prior to insertion into the plasma membrane, 3 h after its synthesis, the alpha' and beta' precursors are converted to mature receptor comprised of alpha-(135 kDa) and beta-(95 kDa) subunits. The 125 kDa alpha'- and 83 kDa beta'-subunit precursors are endoglycosidase H-sensitive and their oligosaccharide chains do not contain terminal sialic acid. Just prior to insertion into the plasma membrane the alpha' and beta' precursors are sialylated, apparently in the Golgi apparatus, giving rise to the 135 kDa alpha and 95 kDa beta receptor subunits and become Endo H-resistant and neuraminidase-sensitive. A proposed sequence of post-translational processing events for the insulin proreceptor is shown in Figure 10.(ABSTRACT TRUNCATED AT 400 WORDS)
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