1
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Sindhu T, Rajamanikandan S, Jeyakanthan J, Pal D. Investigation of protein-ligand binding motions through protein conformational morphing and clustering of cytochrome bc1-aa3 super complex. J Mol Graph Model 2023; 118:108347. [PMID: 36208591 DOI: 10.1016/j.jmgm.2022.108347] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2022] [Revised: 09/18/2022] [Accepted: 09/23/2022] [Indexed: 11/19/2022]
Abstract
Cytochrome b (QcrB) is considered an essential subunit in the electron transport chain that coordinates the action of the entire cytochrome bc1 oxidase. It has been identified as an attractive drug target for a new promising clinical candidate Q203 that depletes the intracellular ATP levels in the bacterium, Mycobacterium tuberculosis. However, single point polymorphism (T313A/I) near the quinol oxidation site of QcrB developed resistance to Q203. In the present study, we analyze the structural changes and drug-resistance mechanism of QcrB due to the point mutation in detail through conformational morphing and molecular docking studies. By morphing, we generated conformers between the open and closed state of the electron transporting cytochrome bc1-aa3 super complex. We clustered them to identify four intermediate structures and relevant intra- and intermolecular motions that may be of functional relevance, especially the binding of Q203 in wild and mutant QcrB intermediate structures and their alteration in developing drug resistance. The difference in the binding score and hydrogen bond interactions between Q203 and the wild-type and mutant intermediate structures of QcrB from molecular docking studies showed that the point mutation T313A severely affected the binding affinity of the candidate drug. Together, the findings provide an in-depth understanding of QcrB inhibition in different conformations, including closed, intermediate, and open states of cytochrome bc1-aa3 super complex in Mycobacterium tuberculosis at the atomic level. We also obtain insights for designing QcrB and cytochrome bc1-aa3 inhibitors as potential therapeutics that may combat drug resistance in tuberculosis.
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Affiliation(s)
- Thangaraj Sindhu
- Department of Computational and Data Sciences, Indian Institute of Science, Bangalore, Karnataka, India
| | - Sundarraj Rajamanikandan
- Research and Development Wing, Sree Balaji Medical College and Hospital (BIHER), Chennai, Tamil Nadu, India
| | | | - Debnath Pal
- Department of Computational and Data Sciences, Indian Institute of Science, Bangalore, Karnataka, India.
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2
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He Y, Haque MM, Stuehr DJ, Lu HP. Conformational States and Fluctuations in Endothelial Nitric Oxide Synthase under Calmodulin Regulation. Biophys J 2021; 120:5196-5206. [PMID: 34748763 DOI: 10.1016/j.bpj.2021.11.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Revised: 09/30/2021] [Accepted: 11/02/2021] [Indexed: 11/30/2022] Open
Abstract
Mechanisms that regulate nitric oxide synthase enzymes (NOS) are of interest in biology and medicine. Although NOS catalysis relies on domain motions and is activated by calmodulin (CaM) binding, the relationships are unclear. We used single-molecule fluorescence resonance energy transfer (FRET) spectroscopy to elucidate the conformational states distribution and associated conformational fluctuation dynamics of the two NOS electron transfer domains in a FRET dye-labeled endothelial NOS reductase domain (eNOSr) and to understand how CaM affects the dynamics to regulate catalysis by shaping the spatial and temporal conformational behaviors of eNOSr. In addition, we developed and applied a new imaging approach capable of recording 3D FRET efficiency vs time images to characterize the impact on dynamic conformal states of the eNOSr enzyme by the binding of CaM, which identifies clearly that CaM binding generates an extra new open state of eNOSr, resolving more detailed NOS conformational states and their fluctuation dynamics. We identified a new output state that has an extra-open FAD-FMN conformation that is only populated in the CaM-bound eNOSr. This may reveal the critical role of CaM in triggering NOS activity as it gives conformational flexibility for eNOSr to assume the electron transfer output FMN-Heme state. Our results provide a dynamic link to recently reported EM static structure analyses and demonstrate a capable approach in probing and simultaneously analyzing all of the conformational states, their fluctuations, and the fluctuation dynamics for understanding the mechanism of NOS electron transfer, involving electron transfer amongst FAD, FMN, and Heme domains, during NO synthesis.
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Affiliation(s)
- Yufan He
- Center for Photochemical Sciences, Department of Chemistry, Bowling Green State University, Bowling Green, Ohio 43403
| | - Mohammad Mahfuzul Haque
- Department of Inflammation and Immunology, Lerner Research Institute, The Cleveland Clinic, 9500 Euclid Avenue, Cleveland Clinic, Cleveland, Ohio, 44195
| | - Dennis J Stuehr
- Department of Inflammation and Immunology, Lerner Research Institute, The Cleveland Clinic, 9500 Euclid Avenue, Cleveland Clinic, Cleveland, Ohio, 44195.
| | - H Peter Lu
- Center for Photochemical Sciences, Department of Chemistry, Bowling Green State University, Bowling Green, Ohio 43403.
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3
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Bárta F, Dedíková A, Bebová M, Dušková Š, Mráz J, Schmeiser HH, Arlt VM, Hodek P, Stiborová M. Co-Exposure to Aristolochic Acids I and II Increases DNA Adduct Formation Responsible for Aristolochic Acid I-Mediated Carcinogenicity in Rats. Int J Mol Sci 2021; 22:ijms221910479. [PMID: 34638820 PMCID: PMC8509051 DOI: 10.3390/ijms221910479] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2021] [Revised: 09/20/2021] [Accepted: 09/23/2021] [Indexed: 11/16/2022] Open
Abstract
The plant extract aristolochic acid (AA), containing aristolochic acids I (AAI) and II (AAII) as major components, causes aristolochic acid nephropathy (AAN) and Balkan endemic nephropathy (BEN), unique renal diseases associated with upper urothelial cancer. Recently (Chemical Research in Toxicology 33(11), 2804–2818, 2020), we showed that the in vivo metabolism of AAI and AAII in Wistar rats is influenced by their co-exposure (i.e., AAI/AAII mixture). Using the same rat model, we investigated how exposure to the AAI/AAII mixture can influence AAI and AAII DNA adduct formation (i.e., AA-mediated genotoxicity). Using 32P-postlabelling, we found that AA-DNA adduct formation was increased in the livers and kidneys of rats treated with AAI/AAII mixture compared to rats treated with AAI or AAII alone. Measuring the activity of enzymes involved in AA metabolism, we showed that enhanced AA-DNA adduct formation might be caused partially by both decreased AAI detoxification as a result of hepatic CYP2C11 inhibition during treatment with AAI/AAII mixture and by hepatic or renal NQO1 induction, the key enzyme predominantly activating AA to DNA adducts. Moreover, our results indicate that AAII might act as an inhibitor of AAI detoxification in vivo. Consequently, higher amounts of AAI might remain in liver and kidney tissues, which can be reductively activated, resulting in enhanced AAI DNA adduct formation. Collectively, these results indicate that AAII present in the plant extract AA enhances the genotoxic properties of AAI (i.e., AAI DNA adduct formation). As patients suffering from AAN and BEN are always exposed to the plant extract (i.e., AAI/AAII mixture), our findings are crucial to better understanding host factors critical for AAN- and BEN-associated urothelial malignancy.
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Affiliation(s)
- František Bárta
- Department of Biochemistry, Faculty of Science, Charles University, Albertov 2030, 128 40 Prague 2, Czech Republic; (F.B.); (A.D.); (M.B.); (P.H.); (M.S.)
| | - Alena Dedíková
- Department of Biochemistry, Faculty of Science, Charles University, Albertov 2030, 128 40 Prague 2, Czech Republic; (F.B.); (A.D.); (M.B.); (P.H.); (M.S.)
| | - Michaela Bebová
- Department of Biochemistry, Faculty of Science, Charles University, Albertov 2030, 128 40 Prague 2, Czech Republic; (F.B.); (A.D.); (M.B.); (P.H.); (M.S.)
| | - Šárka Dušková
- Centre of Occupational Health, National Institute of Public Health, Šrobárova 48, 100 42 Prague 10, Czech Republic; (Š.D.); (J.M.)
| | - Jaroslav Mráz
- Centre of Occupational Health, National Institute of Public Health, Šrobárova 48, 100 42 Prague 10, Czech Republic; (Š.D.); (J.M.)
| | - Heinz H. Schmeiser
- Division of Radiopharmaceutical Chemistry, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany;
| | - Volker M. Arlt
- Department of Analytical, Environmental and Forensic Sciences Division, King’s College London, 150 Stamford Street, London SE1 9NH, UK
- Toxicology Department, GAB Consulting GmbH, Heinrich-Fuchs-Str. 96, 69126 Heidelberg, Germany
- Correspondence: ; Tel.: +49-6221-432018-0
| | - Petr Hodek
- Department of Biochemistry, Faculty of Science, Charles University, Albertov 2030, 128 40 Prague 2, Czech Republic; (F.B.); (A.D.); (M.B.); (P.H.); (M.S.)
| | - Marie Stiborová
- Department of Biochemistry, Faculty of Science, Charles University, Albertov 2030, 128 40 Prague 2, Czech Republic; (F.B.); (A.D.); (M.B.); (P.H.); (M.S.)
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4
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Hubbard PA, Xia C, Shen AL, Kim JJP. Structural and kinetic investigations of the carboxy terminus of NADPH-cytochrome P450 oxidoreductase. Arch Biochem Biophys 2021; 701:108792. [PMID: 33556357 PMCID: PMC8020834 DOI: 10.1016/j.abb.2021.108792] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Revised: 01/20/2021] [Accepted: 01/31/2021] [Indexed: 01/04/2023]
Abstract
The influence of the side chains and positioning of the carboxy-terminal residues of NADPH-cytochrome P450 oxidoreductase (CYPOR) on catalytic activity, structure of the carboxy terminus, and interaction with cofactors has been investigated. A tandem deletion of residues Asp675 and Val676, that was expected to shift the position of the functionally important Trp677, resulted in higher cytochrome c reductase activity than that expected from previous studies on the importance of Asp675 and Trp677 in catalysis. Crystallographic determination of the structure of this variant revealed two conformations of the carboxy terminus. In one conformation (Mol A), the last α-helix is partially unwound, resulting in repositioning of all subsequent residues in β-strand 21, from Arg671 to Leu674 (corresponding to Ser673 and Val676 in the wild type structure). This results in the two C-terminal residues, Trp677 and Ser678, being maintained in their wild type positions, with the indole ring of Trp677 stacked against the isoalloxazine ring of FAD as seen in the wild type structure, and Ser673 occupying a similar position to the catalytic residue, Asp675. The other, more disordered conformation is a mixture of the Mol A conformation and one in which the last α-helix is not unwound and the nicotinamide ring is in one of two conformations, out towards the protein surface as observed in the wild type structure (1AMO), or stacked against the flavin ring, similar to that seen in the W677X structure that lacks Trp677 and Ser678 (1JA0). Further kinetic analysis on additional variants showed deletion or substitution of alanine or glycine for Trp677 in conjunction with deletion of Ser678 produced alterations in interactions of CYPOR with NADP+, 2'5'-ADP, and 2'-AMP, as well as the pH dependence of cytochrome c reductase activity. We postulate that deletion of bulky residues at the carboxy terminus permits increased mobility leading to decreased affinity for the 2'5'-ADP and 2'-AMP moieties of NADP+ and subsequent domain movement.
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Affiliation(s)
- Paul A Hubbard
- Department of Biochemistry, Medical College of Wisconsin, Milwaukee, WI, 53226, USA
| | - Chuanwu Xia
- Department of Biochemistry, Medical College of Wisconsin, Milwaukee, WI, 53226, USA
| | - Anna L Shen
- McArdle Laboratory for Cancer Research, Department of Oncology, University of Wisconsin School of Medicine and Public Health, Madison, WI, 53706, USA
| | - Jung-Ja P Kim
- Department of Biochemistry, Medical College of Wisconsin, Milwaukee, WI, 53226, USA.
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5
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Sugishima M, Wada K, Fukuyama K. Recent Advances in the Understanding of the Reaction Chemistries of the Heme Catabolizing Enzymes HO and BVR Based on High Resolution Protein Structures. Curr Med Chem 2020; 27:3499-3518. [PMID: 30556496 PMCID: PMC7509768 DOI: 10.2174/0929867326666181217142715] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Revised: 11/21/2018] [Accepted: 12/11/2018] [Indexed: 01/15/2023]
Abstract
In mammals, catabolism of the heme group is indispensable for life. Heme is first cleaved by the enzyme Heme Oxygenase (HO) to the linear tetrapyrrole Biliverdin IXα (BV), and BV is then converted into bilirubin by Biliverdin Reductase (BVR). HO utilizes three Oxygen molecules (O2) and seven electrons supplied by NADPH-cytochrome P450 oxidoreductase (CPR) to open the heme ring and BVR reduces BV through the use of NAD(P)H. Structural studies of HOs, including substrate-bound, reaction intermediate-bound, and several specific inhibitor-bound forms, reveal details explaining substrate binding to HO and mechanisms underlying-specific HO reaction progression. Cryo-trapped structures and a time-resolved spectroscopic study examining photolysis of the bond between the distal ligand and heme iron demonstrate how CO, produced during the HO reaction, dissociates from the reaction site with a corresponding conformational change in HO. The complex structure containing HO and CPR provides details of how electrons are transferred to the heme-HO complex. Although the tertiary structure of BVR and its complex with NAD+ was determined more than 10 years ago, the catalytic residues and the reaction mechanism of BVR remain unknown. A recent crystallographic study examining cyanobacterial BVR in complex with NADP+ and substrate BV provided some clarification regarding these issues. Two BV molecules are bound to BVR in a stacked manner, and one BV may assist in the reductive catalysis of the other BV. In this review, recent advances illustrated by biochemical, spectroscopic, and crystallographic studies detailing the chemistry underlying the molecular mechanism of HO and BVR reactions are presented.
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Affiliation(s)
- Masakazu Sugishima
- Department of Medical Biochemistry, Kurume University School of Medicine, Kurume, Japan
| | - Kei Wada
- Department of Medical Sciences, University of Miyazaki, Miyazaki, Japan
| | - Keiichi Fukuyama
- Department of Biological Sciences, Graduate School of Science, Osaka University, Toyonaka, Japan.,Department of Applied Chemistry, Graduate School of Engineering, Osaka University, Suita, Japan
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Sugishima M, Taira J, Sagara T, Nakao R, Sato H, Noguchi M, Fukuyama K, Yamamoto K, Yasunaga T, Sakamoto H. Conformational Equilibrium of NADPH-Cytochrome P450 Oxidoreductase Is Essential for Heme Oxygenase Reaction. Antioxidants (Basel) 2020; 9:antiox9080673. [PMID: 32731542 PMCID: PMC7464098 DOI: 10.3390/antiox9080673] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Revised: 07/17/2020] [Accepted: 07/22/2020] [Indexed: 01/01/2023] Open
Abstract
Heme oxygenase (HO) catalyzes heme degradation using electrons supplied by NADPH-cytochrome P450 oxidoreductase (CPR). Electrons from NADPH flow first to FAD, then to FMN, and finally to the heme in the redox partner. Previous biophysical analyses suggest the presence of a dynamic equilibrium between the open and the closed forms of CPR. We previously demonstrated that the open-form stabilized CPR (ΔTGEE) is tightly bound to heme-HO-1, whereas the reduction in heme-HO-1 coupled with ΔTGEE is considerably slow because the distance between FAD and FMN in ΔTGEE is inappropriate for electron transfer from FAD to FMN. Here, we characterized the enzymatic activity and the reduction kinetics of HO-1 using the closed-form stabilized CPR (147CC514). Additionally, we analyzed the interaction between 147CC514 and heme-HO-1 by analytical ultracentrifugation. The results indicate that the interaction between 147CC514 and heme-HO-1 is considerably weak, and the enzymatic activity of 147CC514 is markedly weaker than that of CPR. Further, using cryo-electron microscopy, we confirmed that the crystal structure of ΔTGEE in complex with heme-HO-1 is similar to the relatively low-resolution structure of CPR complexed with heme-HO-1 in solution. We conclude that the "open-close" transition of CPR is indispensable for electron transfer from CPR to heme-HO-1.
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Affiliation(s)
- Masakazu Sugishima
- Department of Medical Biochemistry, Kurume University School of Medicine, 67 Asahi-machi, Kurume 830-0011, Japan; (H.S.); (M.N.); (K.Y.)
- Correspondence: (M.S.); (H.S.)
| | - Junichi Taira
- Department of Bioscience and Bioinformatics, Graduate School of Computer Science and Systems Engineering, Kyushu Institute of Technology, 680-4 Kawazu, Iizuka 820-8502, Japan; (J.T.); (T.S.); (R.N.); (T.Y.)
| | - Tatsuya Sagara
- Department of Bioscience and Bioinformatics, Graduate School of Computer Science and Systems Engineering, Kyushu Institute of Technology, 680-4 Kawazu, Iizuka 820-8502, Japan; (J.T.); (T.S.); (R.N.); (T.Y.)
| | - Ryota Nakao
- Department of Bioscience and Bioinformatics, Graduate School of Computer Science and Systems Engineering, Kyushu Institute of Technology, 680-4 Kawazu, Iizuka 820-8502, Japan; (J.T.); (T.S.); (R.N.); (T.Y.)
| | - Hideaki Sato
- Department of Medical Biochemistry, Kurume University School of Medicine, 67 Asahi-machi, Kurume 830-0011, Japan; (H.S.); (M.N.); (K.Y.)
| | - Masato Noguchi
- Department of Medical Biochemistry, Kurume University School of Medicine, 67 Asahi-machi, Kurume 830-0011, Japan; (H.S.); (M.N.); (K.Y.)
| | - Keiichi Fukuyama
- Department of Biological Sciences, Graduate School of Science, Osaka University, 1-1 Machikaneyama-cho, Toyonaka 560-0043, Japan;
| | - Ken Yamamoto
- Department of Medical Biochemistry, Kurume University School of Medicine, 67 Asahi-machi, Kurume 830-0011, Japan; (H.S.); (M.N.); (K.Y.)
| | - Takuo Yasunaga
- Department of Bioscience and Bioinformatics, Graduate School of Computer Science and Systems Engineering, Kyushu Institute of Technology, 680-4 Kawazu, Iizuka 820-8502, Japan; (J.T.); (T.S.); (R.N.); (T.Y.)
| | - Hiroshi Sakamoto
- Department of Bioscience and Bioinformatics, Graduate School of Computer Science and Systems Engineering, Kyushu Institute of Technology, 680-4 Kawazu, Iizuka 820-8502, Japan; (J.T.); (T.S.); (R.N.); (T.Y.)
- Correspondence: (M.S.); (H.S.)
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7
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Biochemical and structural insights into the cytochrome P450 reductase from Candida tropicalis. Sci Rep 2019; 9:20088. [PMID: 31882753 PMCID: PMC6934812 DOI: 10.1038/s41598-019-56516-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2019] [Accepted: 12/04/2019] [Indexed: 12/15/2022] Open
Abstract
Cytochrome P450 reductases (CPRs) are diflavin oxidoreductases that supply electrons to type II cytochrome P450 monooxygenases (CYPs). In addition, it can also reduce other proteins and molecules, including cytochrome c, ferricyanide, and different drugs. Although various CPRs have been functionally and structurally characterized, the overall mechanism and its interaction with different redox acceptors remain elusive. One of the main problems regarding electron transfer between CPRs and CYPs is the so-called “uncoupling”, whereby NAD(P)H derived electrons are lost due to the reduced intermediates’ (FAD and FMN of CPR) interaction with molecular oxygen. Additionally, the decay of the iron-oxygen complex of the CYP can also contribute to loss of reducing equivalents during an unproductive reaction cycle. This phenomenon generates reactive oxygen species (ROS), leading to an inefficient reaction. Here, we present the study of the CPR from Candida tropicalis (CtCPR) lacking the hydrophobic N-terminal part (Δ2–22). The enzyme supports the reduction of cytochrome c and ferricyanide, with an estimated 30% uncoupling during the reactions with cytochrome c. The ROS produced was not influenced by different physicochemical conditions (ionic strength, pH, temperature). The X-ray structures of the enzyme were solved with and without its cofactor, NADPH. Both CtCPR structures exhibited the closed conformation. Comparison with the different solved structures revealed an intricate ionic network responsible for the regulation of the open/closed movement of CtCPR.
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8
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Ebrecht AC, van der Bergh N, Harrison STL, Smit MS, Sewell BT, Opperman DJ. Biochemical and structural insights into the cytochrome P450 reductase from Candida tropicalis. Sci Rep 2019; 9:20088. [PMID: 31882753 DOI: 10.1101/711317] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2019] [Accepted: 12/04/2019] [Indexed: 05/28/2023] Open
Abstract
Cytochrome P450 reductases (CPRs) are diflavin oxidoreductases that supply electrons to type II cytochrome P450 monooxygenases (CYPs). In addition, it can also reduce other proteins and molecules, including cytochrome c, ferricyanide, and different drugs. Although various CPRs have been functionally and structurally characterized, the overall mechanism and its interaction with different redox acceptors remain elusive. One of the main problems regarding electron transfer between CPRs and CYPs is the so-called "uncoupling", whereby NAD(P)H derived electrons are lost due to the reduced intermediates' (FAD and FMN of CPR) interaction with molecular oxygen. Additionally, the decay of the iron-oxygen complex of the CYP can also contribute to loss of reducing equivalents during an unproductive reaction cycle. This phenomenon generates reactive oxygen species (ROS), leading to an inefficient reaction. Here, we present the study of the CPR from Candida tropicalis (CtCPR) lacking the hydrophobic N-terminal part (Δ2-22). The enzyme supports the reduction of cytochrome c and ferricyanide, with an estimated 30% uncoupling during the reactions with cytochrome c. The ROS produced was not influenced by different physicochemical conditions (ionic strength, pH, temperature). The X-ray structures of the enzyme were solved with and without its cofactor, NADPH. Both CtCPR structures exhibited the closed conformation. Comparison with the different solved structures revealed an intricate ionic network responsible for the regulation of the open/closed movement of CtCPR.
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Affiliation(s)
- Ana C Ebrecht
- Department of Microbial, Biochemical, and Food Biotechnology, University of the Free State, Bloemfontein, 9301, South Africa
- South African DST-NRF Centre of Excellence in Catalysis (c*Change), University of Cape Town, Private Bag, Rondebosch, Cape Town, 7701, South Africa
| | - Naadia van der Bergh
- Centre for Bioprocess Engineering Research (CeBER), Department of Chemical Engineering, University of Cape Town, Rondebosch, Cape Town, 7701, South Africa
- South African DST-NRF Centre of Excellence in Catalysis (c*Change), University of Cape Town, Private Bag, Rondebosch, Cape Town, 7701, South Africa
| | - Susan T L Harrison
- Centre for Bioprocess Engineering Research (CeBER), Department of Chemical Engineering, University of Cape Town, Rondebosch, Cape Town, 7701, South Africa
- South African DST-NRF Centre of Excellence in Catalysis (c*Change), University of Cape Town, Private Bag, Rondebosch, Cape Town, 7701, South Africa
| | - Martha S Smit
- Department of Microbial, Biochemical, and Food Biotechnology, University of the Free State, Bloemfontein, 9301, South Africa
- South African DST-NRF Centre of Excellence in Catalysis (c*Change), University of Cape Town, Private Bag, Rondebosch, Cape Town, 7701, South Africa
| | - B Trevor Sewell
- Structural Biology Research Unit, Department of Integrative Biomedical Sciences, Institute for Infectious Diseases and Molecular Medicine, University of Cape Town, Cape Town, 7700, South Africa.
| | - Diederik J Opperman
- Department of Microbial, Biochemical, and Food Biotechnology, University of the Free State, Bloemfontein, 9301, South Africa.
- South African DST-NRF Centre of Excellence in Catalysis (c*Change), University of Cape Town, Private Bag, Rondebosch, Cape Town, 7701, South Africa.
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9
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Coupling of Redox and Structural States in Cytochrome P450 Reductase Studied by Molecular Dynamics Simulation. Sci Rep 2019; 9:9341. [PMID: 31249341 PMCID: PMC6597723 DOI: 10.1038/s41598-019-45690-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2019] [Accepted: 06/10/2019] [Indexed: 01/09/2023] Open
Abstract
Cytochrome P450 reductase (CPR) is the key protein that regulates the electron transfer from NADPH to various heme-containing monooxygenases. CPR has two flavin-containing domains: one with flavin adenine dinucleotide (FAD), called FAD domain, and the other with flavin mononucleotide (FMN), called FMN domain. It is considered that the electron transfer occurs via FAD and FMN (NADPH → FAD → FMN → monooxygenase) and is regulated by an interdomain open-close motion. It is generally thought that the structural state is coupled with the redox state, which, however, has not yet been firmly established. In this report, we studied the coupling of the redox and the structural states by full-scale molecular dynamics (MD) simulation of CPR (total 86.4 μs). Our MD result showed that while CPR predominantly adopts the closed state both in the oxidized and reduced states, it exhibits a tendency to open in the reduced state. We also found a correlation between the FAD-FMN distance and the predicted FMN-monooxygenase distance, which is embedded in the equilibrium thermal fluctuation of CPR. Based on these results, a physical mechanism for the electron transfer by CPR is discussed.
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10
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Hedison TM, Scrutton NS. Tripping the light fantastic in membrane redox biology: linking dynamic structures to function in ER electron transfer chains. FEBS J 2019; 286:2004-2017. [PMID: 30657259 PMCID: PMC6563164 DOI: 10.1111/febs.14757] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2018] [Revised: 12/16/2018] [Accepted: 01/15/2019] [Indexed: 12/19/2022]
Abstract
How the dynamics of proteins assist catalysis is a contemporary issue in enzymology. In particular, this holds true for membrane‐bound enzymes, where multiple structural, spectroscopic and biochemical approaches are needed to build up a comprehensive picture of how dynamics influence enzyme reaction cycles. Of note are the recent studies of cytochrome P450 reductases (CPR)–P450 (CYP) endoplasmic reticulum redox chains, showing the relationship between dynamics and electron flow through flavin and haem redox centres and the impact this has on monooxygenation chemistry. These studies have led to deeper understanding of mechanisms of electron flow, including the timing and control of electron delivery to protein‐bound cofactors needed to facilitate CYP‐catalysed reactions. Individual and multiple component systems have been used to capture biochemical behaviour and these have led to the emergence of more integrated models of catalysis. Crucially, the effects of membrane environment and composition on reaction cycle chemistry have also been probed, including effects on coenzyme binding/release, thermodynamic control of electron transfer, conformational coupling between partner proteins and vectorial versus ‘off pathway’ electron flow. Here, we review these studies and discuss evidence for the emergence of dynamic structural models of electron flow along human microsomal CPR–P450 redox chains.
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Affiliation(s)
- Tobias M Hedison
- Manchester Institute of Biotechnology and School of Chemistry, University of Manchester, UK
| | - Nigel S Scrutton
- Manchester Institute of Biotechnology and School of Chemistry, University of Manchester, UK
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11
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Quast RB, Fatemi F, Kranendonk M, Margeat E, Truan G. Accurate Determination of Human CPR Conformational Equilibrium by smFRET Using Dual Orthogonal Noncanonical Amino Acid Labeling. Chembiochem 2019; 20:659-666. [DOI: 10.1002/cbic.201800607] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2018] [Indexed: 12/26/2022]
Affiliation(s)
- Robert B. Quast
- LISBP; Université de Toulouse; CNRS; INRA; INSA; 135 Avenue de Rangueil 31077 Toulouse France
| | - Fataneh Fatemi
- Protein Research Center; Shahid Beheshti University, G.C.; Evin 1983969411 Tehran Iran
| | - Michel Kranendonk
- Center for Toxicogenomics and Human Health (ToxOmics); Genetics, Oncology and Human Toxicology; NOVA Medical School; Faculdade de Ciências Médicas; Universidade Nova de Lisboa; Rua Câmara Pestana, no. 6 1150-082 Lisboa Portugal
| | - Emmanuel Margeat
- BS; CNRS; CINSERM; Université de Montpellier; Montpellier France
| | - Gilles Truan
- LISBP; Université de Toulouse; CNRS; INRA; INSA; 135 Avenue de Rangueil 31077 Toulouse France
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12
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Molecular mechanism of metabolic NAD(P)H-dependent electron-transfer systems: The role of redox cofactors. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2018; 1860:233-258. [PMID: 30419202 DOI: 10.1016/j.bbabio.2018.11.014] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2018] [Revised: 10/30/2018] [Accepted: 11/07/2018] [Indexed: 12/14/2022]
Abstract
NAD(P)H-dependent electron-transfer (ET) systems require three functional components: a flavin-containing NAD(P)H-dehydrogenase, one-electron carrier and metal-containing redox center. In principle, these ET systems consist of one-, two- and three-components, and the electron flux from pyridine nucleotide cofactors, NADPH or NADH to final electron acceptor follows a linear pathway: NAD(P)H → flavin → one-electron carrier → metal containing redox center. In each step ET is primarily controlled by one- and two-electron midpoint reduction potentials of protein-bound redox cofactors in which the redox-linked conformational changes during the catalytic cycle are required for the domain-domain interactions. These interactions play an effective ET reactions in the multi-component ET systems. The microsomal and mitochondrial cytochrome P450 (cyt P450) ET systems, nitric oxide synthase (NOS) isozymes, cytochrome b5 (cyt b5) ET systems and methionine synthase (MS) ET system include a combination of multi-domain, and their organizations display similarities as well as differences in their components. However, these ET systems are sharing of a similar mechanism. More recent structural information obtained by X-ray and cryo-electron microscopy (cryo-EM) analysis provides more detail for the mechanisms associated with multi-domain ET systems. Therefore, this review summarizes the roles of redox cofactors in the metabolic ET systems on the basis of one-electron redox potentials. In final Section, evolutionary aspects of NAD(P)H-dependent multi-domain ET systems will be discussed.
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13
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Šrejber M, Navrátilová V, Paloncýová M, Bazgier V, Berka K, Anzenbacher P, Otyepka M. Membrane-attached mammalian cytochromes P450: An overview of the membrane's effects on structure, drug binding, and interactions with redox partners. J Inorg Biochem 2018; 183:117-136. [DOI: 10.1016/j.jinorgbio.2018.03.002] [Citation(s) in RCA: 81] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2017] [Revised: 02/16/2018] [Accepted: 03/01/2018] [Indexed: 01/08/2023]
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14
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Direct observation of multiple conformational states in Cytochrome P450 oxidoreductase and their modulation by membrane environment and ionic strength. Sci Rep 2018; 8:6817. [PMID: 29717147 PMCID: PMC5931563 DOI: 10.1038/s41598-018-24922-x] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2017] [Accepted: 04/03/2018] [Indexed: 12/20/2022] Open
Abstract
Cytochrome P450 oxidoreductase (POR) is the primary electron donor in eukaryotic cytochrome P450 (CYP) containing systems. A wealth of ensemble biophysical studies of Cytochrome P450 oxidoreductase (POR) has reported a binary model of the conformational equilibrium directing its catalytic efficiency and biomolecular recognition. In this study, full length POR from the crop plant Sorghum bicolor was site-specifically labeled with Cy3 (donor) and Cy5 (acceptor) fluorophores and reconstituted in nanodiscs. Our single molecule fluorescence resonance energy transfer (smFRET) burst analyses of POR allowed the direct observation and quantification of at least three dominant conformational sub-populations, their distribution and occupancies. Moreover, the state occupancies were remodeled significantly by ionic strength and the nature of reconstitution environment, i.e. phospholipid bilayers (nanodiscs) composed of different lipid head group charges vs. detergent micelles. The existence of conformational heterogeneity in POR may mediate selective activation of multiple downstream electron acceptors and association in complexes in the ER membrane.
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15
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Boehr DD, D'Amico RN, O'Rourke KF. Engineered control of enzyme structural dynamics and function. Protein Sci 2018; 27:825-838. [PMID: 29380452 DOI: 10.1002/pro.3379] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2017] [Revised: 01/20/2018] [Accepted: 01/24/2018] [Indexed: 12/20/2022]
Abstract
Enzymes undergo a range of internal motions from local, active site fluctuations to large-scale, global conformational changes. These motions are often important for enzyme function, including in ligand binding and dissociation and even preparing the active site for chemical catalysis. Protein engineering efforts have been directed towards manipulating enzyme structural dynamics and conformational changes, including targeting specific amino acid interactions and creation of chimeric enzymes with new regulatory functions. Post-translational covalent modification can provide an additional level of enzyme control. These studies have not only provided insights into the functional role of protein motions, but they offer opportunities to create stimulus-responsive enzymes. These enzymes can be engineered to respond to a number of external stimuli, including light, pH, and the presence of novel allosteric modulators. Altogether, the ability to engineer and control enzyme structural dynamics can provide new tools for biotechnology and medicine.
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Affiliation(s)
- David D Boehr
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania, 16802, USA
| | - Rebecca N D'Amico
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania, 16802, USA
| | - Kathleen F O'Rourke
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania, 16802, USA
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16
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Xia C, Rwere F, Im S, Shen AL, Waskell L, Kim JJP. Structural and Kinetic Studies of Asp632 Mutants and Fully Reduced NADPH-Cytochrome P450 Oxidoreductase Define the Role of Asp632 Loop Dynamics in the Control of NADPH Binding and Hydride Transfer. Biochemistry 2018; 57:945-962. [PMID: 29308883 PMCID: PMC5967631 DOI: 10.1021/acs.biochem.7b01102] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Conformational changes in NADPH-cytochrome P450 oxidoreductase (CYPOR) associated with electron transfer from NADPH to electron acceptors via FAD and FMN have been investigated via structural studies of the four-electron-reduced NADP+-bound enzyme and kinetic and structural studies of mutants that affect the conformation of the mobile Gly631-Asn635 loop (Asp632 loop). The structure of four-electron-reduced, NADP+-bound wild type CYPOR shows the plane of the nicotinamide ring positioned perpendicular to the FAD isoalloxazine with its carboxamide group forming H-bonds with N1 of the flavin ring and the Thr535 hydroxyl group. In the reduced enzyme, the C8-C8 atoms of the two flavin rings are ∼1 Å closer than in the fully oxidized and one-electron-reduced structures, which suggests that flavin reduction facilitates interflavin electron transfer. Structural and kinetic studies of mutants Asp632Ala, Asp632Phe, Asp632Asn, and Asp632Glu demonstrate that the carboxyl group of Asp632 is important for stabilizing the Asp632 loop in a retracted position that is required for the binding of the NADPH ribityl-nicotinamide in a hydride-transfer-competent conformation. Structures of the mutants and reduced wild type CYPOR permit us to identify a possible pathway for NADP(H) binding to and release from CYPOR. Asp632 mutants unable to form stable H-bonds with the backbone amides of Arg634, Asn635, and Met636 exhibit decreased catalytic activity and severely impaired hydride transfer from NADPH to FAD, but leave interflavin electron transfer intact. Intriguingly, the Arg634Ala mutation slightly increases the cytochrome P450 2B4 activity. We propose that Asp632 loop movement, in addition to facilitating NADP(H) binding and release, participates in domain movements modulating interflavin electron transfer.
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Affiliation(s)
- Chuanwu Xia
- Medical College of Wisconsin, Milwaukee, Wisconsin 53226
| | - Freeborn Rwere
- University of Michigan Medical School, Ann Arbor, Michigan 48105
| | - Sangchoul Im
- University of Michigan Medical School, Ann Arbor, Michigan 48105
| | - Anna L. Shen
- McArdle Laboratory for Cancer Research, University of Wisconsin-Madison, Madison, Wisconsin 53706
| | - Lucy Waskell
- University of Michigan Medical School, Ann Arbor, Michigan 48105,Corresponding Author: Correspondence should be addressed to Lucy Waskell, M.D., Ph.D., Department of Anesthesiology, University of Michigan, Mail Stop 151, 2215 Fuller Rd., Ann Arbor, MI 48109-0112. . OR Jung Ja Kim, Ph.D., Department of Biochemistry, Medical College of Wisconsin, 8701 Watertown Plank Rd., Milwaukee, WI 53226.
| | - Jung-Ja P. Kim
- Medical College of Wisconsin, Milwaukee, Wisconsin 53226,Corresponding Author: Correspondence should be addressed to Lucy Waskell, M.D., Ph.D., Department of Anesthesiology, University of Michigan, Mail Stop 151, 2215 Fuller Rd., Ann Arbor, MI 48109-0112. . OR Jung Ja Kim, Ph.D., Department of Biochemistry, Medical College of Wisconsin, 8701 Watertown Plank Rd., Milwaukee, WI 53226.
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17
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Liu K, Hughes JMX, Hay S, Scrutton NS. Liver microsomal lipid enhances the activity and redox coupling of colocalized cytochrome P450 reductase-cytochrome P450 3A4 in nanodiscs. FEBS J 2017; 284:2302-2319. [PMID: 28618157 PMCID: PMC5575521 DOI: 10.1111/febs.14129] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2017] [Revised: 06/01/2017] [Accepted: 06/05/2017] [Indexed: 01/22/2023]
Abstract
The haem-containing mono-oxygenase cytochrome P450 3A4 (CYP3A4) and its redox partner NADPH-dependent cytochrome P450 oxidoreductase (CPR) are among the most important enzymes in human liver for metabolizing drugs and xenobiotic compounds. They are membrane-bound in the endoplasmic reticulum (ER). How ER colocalization and the complex ER phospholipid composition influence enzyme activity are not well understood. CPR and CYP3A4 were incorporated into phospholipid bilayer nanodiscs, both singly, and together in a 1 : 1 ratio, to investigate the significance of membrane insertion and the influence of varying membrane composition on steady-state reaction kinetics. Reaction kinetics were analysed using a fluorimetric assay with 7-benzyloxyquinoline as substrate for CYP3A4. Full activity of the mono-oxygenase system, with electron transfer from NADPH via CPR, could only be reconstituted when CPR and CYP3A4 were colocalized within the same nanodiscs. No activity was observed when CPR and CYP3A4 were each incorporated separately into nanodiscs then mixed together, or when soluble forms of CPR were mixed with preassembled CYP3A4-nanodiscs. Membrane integration and colocalization are therefore essential for electron transfer. Liver microsomal lipid had an enhancing effect compared with phosphatidylcholine on the activity of CPR alone in nanodiscs, and a greater enhancing effect on the activity of CPR-CYP3A4 nanodisc complexes, which was not matched by a phospholipid mixture designed to mimic the ER composition. Furthermore, liver lipid enhanced redox coupling within the system. Thus, natural ER lipids possess properties or include components important for enhanced catalysis by CPR-CYP3A4 nanodisc complexes. Our findings demonstrate the importance of using natural lipid preparations for the detailed analysis of membrane protein activity.
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Affiliation(s)
- Kang‐Cheng Liu
- Centre for Synthetic Biology of Fine and Speciality Chemicals (SYNBIOCHEM)School of ChemistryManchester Institute of BiotechnologyThe University of ManchesterUK
| | - John M. X. Hughes
- Centre for Synthetic Biology of Fine and Speciality Chemicals (SYNBIOCHEM)School of ChemistryManchester Institute of BiotechnologyThe University of ManchesterUK
| | - Sam Hay
- Centre for Synthetic Biology of Fine and Speciality Chemicals (SYNBIOCHEM)School of ChemistryManchester Institute of BiotechnologyThe University of ManchesterUK
| | - Nigel S. Scrutton
- Centre for Synthetic Biology of Fine and Speciality Chemicals (SYNBIOCHEM)School of ChemistryManchester Institute of BiotechnologyThe University of ManchesterUK
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18
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Hedison TM, Hay S, Scrutton NS. A perspective on conformational control of electron transfer in nitric oxide synthases. Nitric Oxide 2017; 63:61-67. [PMID: 27619338 PMCID: PMC5295631 DOI: 10.1016/j.niox.2016.09.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2016] [Revised: 09/05/2016] [Accepted: 09/06/2016] [Indexed: 01/20/2023]
Abstract
This perspective reviews single molecule and ensemble fluorescence spectroscopy studies of the three tissue specific nitric oxide synthase (NOS) isoenzymes and the related diflavin oxidoreductase cytochrome P450 reductase. The focus is on the role of protein dynamics and the protein conformational landscape and we discuss how recent fluorescence-based studies have helped in illustrating how the nature of the NOS conformational landscape relates to enzyme turnover and catalysis.
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Affiliation(s)
- Tobias M Hedison
- Manchester Institute of Biotechnology, The University of Manchester, Manchester, United Kingdom
| | - Sam Hay
- Manchester Institute of Biotechnology, The University of Manchester, Manchester, United Kingdom
| | - Nigel S Scrutton
- Manchester Institute of Biotechnology, The University of Manchester, Manchester, United Kingdom.
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19
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Kovrigina EA, Pattengale B, Xia C, Galiakhmetov AR, Huang J, Kim JJP, Kovrigin EL. Conformational States of Cytochrome P450 Oxidoreductase Evaluated by Förster Resonance Energy Transfer Using Ultrafast Transient Absorption Spectroscopy. Biochemistry 2016; 55:5973-5976. [PMID: 27741572 DOI: 10.1021/acs.biochem.6b00623] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
NADPH-cytochrome P450 oxidoreductase (CYPOR) was shown to undergo large conformational rearrangements in its functional cycle. Using a new Förster resonance energy transfer (FRET) approach based on femtosecond transient absorption spectroscopy (TA), we determined the donor-acceptor distance distribution in the reduced and oxidized states of CYPOR. The unmatched time resolution of TA allowed the quantitative assessment of the donor-acceptor FRET, indicating that CYPOR assumes a closed conformation in both reduced and oxidized states in the absence of the redox partner. The described ultrafast TA measurements of FRET with readily available red-infrared fluorescent labels open new opportunities for structural studies in chromophore-rich proteins and their complexes.
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Affiliation(s)
- Elizaveta A Kovrigina
- Biochemistry Department, Medical College of Wisconsin , Milwaukee, Wisconsin 53226, United States.,Chemistry Department, Marquette University , P.O. Box 1881, Milwaukee, Wisconsin 53201, United States
| | - Brian Pattengale
- Chemistry Department, Marquette University , P.O. Box 1881, Milwaukee, Wisconsin 53201, United States
| | - Chuanwu Xia
- Biochemistry Department, Medical College of Wisconsin , Milwaukee, Wisconsin 53226, United States
| | - Azamat R Galiakhmetov
- Chemistry Department, Marquette University , P.O. Box 1881, Milwaukee, Wisconsin 53201, United States
| | - Jier Huang
- Chemistry Department, Marquette University , P.O. Box 1881, Milwaukee, Wisconsin 53201, United States
| | - Jung-Ja P Kim
- Biochemistry Department, Medical College of Wisconsin , Milwaukee, Wisconsin 53226, United States
| | - Evgenii L Kovrigin
- Chemistry Department, Marquette University , P.O. Box 1881, Milwaukee, Wisconsin 53201, United States
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20
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McCammon KM, Panda SP, Xia C, Kim JJP, Moutinho D, Kranendonk M, Auchus RJ, Lafer EM, Ghosh D, Martasek P, Kar R, Masters BS, Roman LJ. Instability of the Human Cytochrome P450 Reductase A287P Variant Is the Major Contributor to Its Antley-Bixler Syndrome-like Phenotype. J Biol Chem 2016; 291:20487-502. [PMID: 27496950 PMCID: PMC5034044 DOI: 10.1074/jbc.m116.716019] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2016] [Revised: 07/18/2016] [Indexed: 11/06/2022] Open
Abstract
Human NADPH-cytochrome P450 oxidoreductase (POR) gene mutations are associated with severe skeletal deformities and disordered steroidogenesis. The human POR mutation A287P presents with disordered sexual development and skeletal malformations. Difficult recombinant expression and purification of this POR mutant suggested that the protein was less stable than WT. The activities of cytochrome P450 17A1, 19A1, and 21A2, critical in steroidogenesis, were similar using our purified, full-length, unmodified A287P or WT POR, as were those of several xenobiotic-metabolizing cytochromes P450, indicating that the A287P protein is functionally competent in vitro, despite its functionally deficient phenotypic behavior in vivo Differential scanning calorimetry and limited trypsinolysis studies revealed a relatively unstable A287P compared with WT protein, leading to the hypothesis that the syndrome observed in vivo results from altered POR protein stability. The crystal structures of the soluble domains of WT and A287P reveal only subtle differences between them, but these differences are consistent with the differential scanning calorimetry results as well as the differential susceptibility of A287P and WT observed with trypsinolysis. The relative in vivo stabilities of WT and A287P proteins were also examined in an osteoblast cell line by treatment with cycloheximide, a protein synthesis inhibitor, showing that the level of A287P protein post-inhibition is lower than WT and suggesting that A287P may be degraded at a higher rate. Current studies demonstrate that, unlike previously described mutations, A287P causes POR deficiency disorder due to conformational instability leading to proteolytic susceptibility in vivo, rather than through an inherent flavin-binding defect.
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Affiliation(s)
- Karen M McCammon
- From the Department of Biochemistry, University of Texas Health Science Center, San Antonio, Texas 78229
| | - Satya P Panda
- From the Department of Biochemistry, University of Texas Health Science Center, San Antonio, Texas 78229
| | - Chuanwu Xia
- the Department of Biochemistry, Medical College of Wisconsin, Milwaukee, Wisconsin 53226
| | - Jung-Ja P Kim
- the Department of Biochemistry, Medical College of Wisconsin, Milwaukee, Wisconsin 53226
| | - Daniela Moutinho
- the Centre for Toxicogenomics and Human Health (ToxOmics), Genetics, Oncology and Human Toxicology, NOVA Medical School/FCM, Universidade Nova de Lisboa, Campo dos Mártires da Pátria, 130, 1169-056 Lisboa, Portugal
| | - Michel Kranendonk
- the Centre for Toxicogenomics and Human Health (ToxOmics), Genetics, Oncology and Human Toxicology, NOVA Medical School/FCM, Universidade Nova de Lisboa, Campo dos Mártires da Pátria, 130, 1169-056 Lisboa, Portugal
| | - Richard J Auchus
- the Division of Metabolism, Endocrinology and Diabetes, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan 48109
| | - Eileen M Lafer
- From the Department of Biochemistry, University of Texas Health Science Center, San Antonio, Texas 78229
| | - Debashis Ghosh
- the Department of Pharmacology, State University of New York Upstate Medical University, Syracuse, New York 13210, and
| | - Pavel Martasek
- the Department of Pediatrics, First Faculty of Medicine, Charles University in Prague and General University Hospital, 116 36 Prague 1, Czech Republic
| | - Rekha Kar
- From the Department of Biochemistry, University of Texas Health Science Center, San Antonio, Texas 78229
| | - Bettie Sue Masters
- From the Department of Biochemistry, University of Texas Health Science Center, San Antonio, Texas 78229,
| | - Linda J Roman
- From the Department of Biochemistry, University of Texas Health Science Center, San Antonio, Texas 78229,
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21
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Hedison TM, Leferink NGH, Hay S, Scrutton NS. Correlating Calmodulin Landscapes with Chemical Catalysis in Neuronal Nitric Oxide Synthase using Time-Resolved FRET and a 5-Deazaflavin Thermodynamic Trap. ACS Catal 2016; 6:5170-5180. [PMID: 27563493 PMCID: PMC4993522 DOI: 10.1021/acscatal.6b01280] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2016] [Revised: 06/23/2016] [Indexed: 11/28/2022]
Abstract
![]()
A major challenge in enzymology is
the need to correlate the dynamic
properties of enzymes with, and understand the impact on, their catalytic
cycles. This is especially the case with large, multicenter enzymes
such as the nitric oxide synthases (NOSs), where the importance of
dynamics has been inferred from a variety of structural, single-molecule,
and ensemble spectroscopic approaches but where motions have not been
correlated experimentally with mechanistic steps in the reaction cycle.
Here we take such an approach. Using time-resolved spectroscopy employing
absorbance and Förster resonance energy transfer (FRET) and
exploiting the properties of a flavin analogue (5-deazaflavin mononucleotide
(5-dFMN)) and isotopically labeled nicotinamide coenzymes, we correlate
the timing of CaM structural changes when bound to neuronal nitric
oxide synthase (nNOS) with the nNOS catalytic cycle. We show that
remodeling of CaM occurs early in the electron transfer sequence (FAD
reduction), not at later points in the reaction cycle (e.g., FMN reduction).
Conformational changes are tightly correlated with FAD reduction kinetics
and reflect a transient “opening” and then “closure”
of the bound CaM molecule. We infer that displacement of the C-terminal
tail on binding NADPH and subsequent FAD reduction are the likely
triggers of conformational change. By combining the use of cofactor/coenzyme
analogues and time-resolved FRET/absorbance spectrophotometry, we
show how the reaction cycles of complex enzymes can be simplified,
enabling a detailed study of the relationship between protein dynamics
and reaction cycle chemistry—an approach that can also be used
with other complex multicenter enzymes.
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Affiliation(s)
- Tobias M. Hedison
- Manchester Synthetic Biology
Research Centre for Fine and Speciality Chemicals (SYNBIOCHEM), Manchester
Institute of Biotechnology, The University of Manchester, Manchester M1 7DN, United Kingdom
| | - Nicole G. H. Leferink
- Manchester Synthetic Biology
Research Centre for Fine and Speciality Chemicals (SYNBIOCHEM), Manchester
Institute of Biotechnology, The University of Manchester, Manchester M1 7DN, United Kingdom
| | - Sam Hay
- Manchester Synthetic Biology
Research Centre for Fine and Speciality Chemicals (SYNBIOCHEM), Manchester
Institute of Biotechnology, The University of Manchester, Manchester M1 7DN, United Kingdom
| | - Nigel S. Scrutton
- Manchester Synthetic Biology
Research Centre for Fine and Speciality Chemicals (SYNBIOCHEM), Manchester
Institute of Biotechnology, The University of Manchester, Manchester M1 7DN, United Kingdom
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22
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A well-balanced preexisting equilibrium governs electron flux efficiency of a multidomain diflavin reductase. Biophys J 2016; 108:1527-1536. [PMID: 25809265 DOI: 10.1016/j.bpj.2015.01.032] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2014] [Revised: 12/24/2014] [Accepted: 01/21/2015] [Indexed: 01/11/2023] Open
Abstract
Diflavin reductases are bidomain electron transfer proteins in which structural reorientation is necessary to account for the various intramolecular and intermolecular electron transfer steps. Using small-angle x-ray scattering and nuclear magnetic resonance data, we describe the conformational free-energy landscape of the NADPH-cytochrome P450 reductase (CPR), a typical bidomain redox enzyme composed of two covalently-bound flavin domains, under various experimental conditions. The CPR enzyme exists in a salt- and pH-dependent rapid equilibrium between a previously described rigid, locked state and a newly characterized, highly flexible, unlocked state. We further establish that maximal electron flux through CPR is conditioned by adjustable stability of the locked-state domain interface under resting conditions. This is rationalized by a kinetic scheme coupling rapid conformational sampling and slow chemical reaction rates. Regulated domain interface stability associated with fast stochastic domain contacts during the catalytic cycle thus provides, to our knowledge, a new paradigm for improving our understanding of multidomain enzyme function.
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23
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He Y, Haque MM, Stuehr DJ, Lu HP. Single-molecule spectroscopy reveals how calmodulin activates NO synthase by controlling its conformational fluctuation dynamics. Proc Natl Acad Sci U S A 2015; 112:11835-40. [PMID: 26311846 PMCID: PMC4586839 DOI: 10.1073/pnas.1508829112] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Mechanisms that regulate the nitric oxide synthase enzymes (NOS) are of interest in biology and medicine. Although NOS catalysis relies on domain motions, and is activated by calmodulin binding, the relationships are unclear. We used single-molecule fluorescence resonance energy transfer (FRET) spectroscopy to elucidate the conformational states distribution and associated conformational fluctuation dynamics of the two electron transfer domains in a FRET dye-labeled neuronal NOS reductase domain, and to understand how calmodulin affects the dynamics to regulate catalysis. We found that calmodulin alters NOS conformational behaviors in several ways: It changes the distance distribution between the NOS domains, shortens the lifetimes of the individual conformational states, and instills conformational discipline by greatly narrowing the distributions of the conformational states and fluctuation rates. This information was specifically obtainable only by single-molecule spectroscopic measurements, and reveals how calmodulin promotes catalysis by shaping the physical and temporal conformational behaviors of NOS.
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Affiliation(s)
- Yufan He
- Center for Photochemical Sciences, Department of Chemistry, Bowling Green State University, Bowling Green, OH 43403
| | - Mohammad Mahfuzul Haque
- Department of Pathobiology, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195
| | - Dennis J Stuehr
- Department of Pathobiology, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195
| | - H Peter Lu
- Center for Photochemical Sciences, Department of Chemistry, Bowling Green State University, Bowling Green, OH 43403;
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24
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Hedison TM, Hay S, Scrutton NS. Real-time analysis of conformational control in electron transfer reactions of human cytochrome P450 reductase with cytochrome c. FEBS J 2015; 282:4357-75. [PMID: 26307151 PMCID: PMC4973710 DOI: 10.1111/febs.13501] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2015] [Revised: 07/21/2015] [Accepted: 08/21/2015] [Indexed: 11/27/2022]
Abstract
Protein domain dynamics and electron transfer chemistry are often associated, but real‐time analysis of domain motion in enzyme‐catalysed reactions and the elucidation of mechanistic schemes that relate these motions to the reaction chemistry are major challenges for biological catalysis research. Previously we suggested that reduction of human cytochrome P450 reductase with the reducing coenzyme NADPH is accompanied by major structural re‐orientation of the FMN‐ and FAD‐binding domains through an inferred dynamic cycle of ‘open’ and ‘closed’ conformations of the enzyme (PLoS Biol, 2011, e1001222). However, these studies were restricted to stopped‐flow/FRET analysis of the reductive half‐reaction, and were compromised by fluorescence quenching of the acceptor by the flavin cofactors. Here we have improved the design of the FRET system, by using dye pairs with near‐IR fluorescence, and extended studies on human cytochrome P450 reductase to the oxidative half‐reaction using a double‐mixing stopped‐flow assay, thereby analysing in real‐time conformational dynamics throughout the complete catalytic cycle. We correlate redox changes accompanying the reaction chemistry with protein dynamic changes observed by FRET, and show that redox chemistry drives a major re‐orientation of the protein domains in both the reductive and oxidative half‐reactions. Our studies using the tractable (soluble) surrogate electron acceptor cytochrome c provide a framework for analysing mechanisms of electron transfer in the endoplasmic reticulum between cytochrome P450 reductase and cognate P450 enzymes. More generally, our work emphasizes the importance of protein dynamics in intra‐ and inter‐protein electron transfer, and establishes methodology for real‐time analysis of structural changes throughout the catalytic cycle of complex redox proteins.
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Affiliation(s)
- Tobias M Hedison
- Manchester Institute of Biotechnology and Faculty of Life Sciences, University of Manchester, UK
| | - Sam Hay
- Manchester Institute of Biotechnology and Faculty of Life Sciences, University of Manchester, UK
| | - Nigel S Scrutton
- Manchester Institute of Biotechnology and Faculty of Life Sciences, University of Manchester, UK
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25
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Bostick CD, Flora DR, Gannett PM, Tracy TS, Lederman D. Nanoscale electron transport measurements of immobilized cytochrome P450 proteins. NANOTECHNOLOGY 2015; 26:155102. [PMID: 25804257 PMCID: PMC4791957 DOI: 10.1088/0957-4484/26/15/155102] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
Gold nanopillars, functionalized with an organic self-assembled monolayer, can be used to measure the electrical conductance properties of immobilized proteins without aggregation. Measurements of the conductance of nanopillars with cytochrome P450 2C9 (CYP2C9) proteins using conducting probe atomic force microscopy demonstrate that a correlation exists between the energy barrier height between hopping sites and CYP2C9 metabolic activity. Measurements performed as a function of tip force indicate that, when subjected to a large force, the protein is more stable in the presence of a substrate. This agrees with the hypothesis that substrate entry into the active site helps to stabilize the enzyme. The relative distance between hopping sites also increases with increasing force, possibly because protein functional groups responsible for electron transport (ETp) depend on the structure of the protein. The inhibitor sulfaphenazole, in addition to the previously studied aniline, increased the barrier height for electron transfer and thereby makes CYP2C9 reduction more difficult and inhibits metabolism. This suggests that P450 Type II binders may decrease the ease of ETp processes in the enzyme, in addition to occupying the active site.
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Affiliation(s)
- Christopher D. Bostick
- Department of Pharmaceutical Sciences, West Virginia University, Morgantown, WV 26506-9530, USA
| | - Darcy R. Flora
- College of Pharmacy, University of Minnesota, Minneapolis, MN 55455, USA
| | - Peter M. Gannett
- Department of Pharmaceutical Sciences, West Virginia University, Morgantown, WV 26506-9530, USA
| | - Timothy S. Tracy
- College of Pharmacy, University of Kentucky, Lexington, KY, 40536, USA
| | - David Lederman
- Department of Physics and Astronomy, West Virginia University, Morgantown, WV 26506-6315, USA
- Address correspondence to
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26
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Hlavica P. Mechanistic basis of electron transfer to cytochromes p450 by natural redox partners and artificial donor constructs. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2015; 851:247-97. [PMID: 26002739 DOI: 10.1007/978-3-319-16009-2_10] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Cytochromes P450 (P450s) are hemoproteins catalyzing oxidative biotransformation of a vast array of natural and xenobiotic compounds. Reducing equivalents required for dioxygen cleavage and substrate hydroxylation originate from different redox partners including diflavin reductases, flavodoxins, ferredoxins and phthalate dioxygenase reductase (PDR)-type proteins. Accordingly, circumstantial analysis of structural and physicochemical features governing donor-acceptor recognition and electron transfer poses an intriguing challenge. Thus, conformational flexibility reflected by togging between closed and open states of solvent exposed patches on the redox components was shown to be instrumental to steered electron transmission. Here, the membrane-interactive tails of the P450 enzymes and donor proteins were recognized to be crucial to proper orientation toward each other of surface sites on the redox modules steering functional coupling. Also, mobile electron shuttling may come into play. While charge-pairing mechanisms are of primary importance in attraction and complexation of the redox partners, hydrophobic and van der Waals cohesion forces play a minor role in docking events. Due to catalytic plasticity of P450 enzymes, there is considerable promise in biotechnological applications. Here, deeper insight into the mechanistic basis of the redox machinery will permit optimization of redox processes via directed evolution and DNA shuffling. Thus, creation of hybrid systems by fusion of the modified heme domain of P450s with proteinaceous electron carriers helps obviate the tedious reconstitution procedure and induces novel activities. Also, P450-based amperometric biosensors may open new vistas in pharmaceutical and clinical implementation and environmental monitoring.
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Affiliation(s)
- Peter Hlavica
- Walther-Straub-Institut für Pharmakologie und Toxikologie der LMU, Goethestrasse 33, 80336, München, Germany,
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27
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Laursen T, Møller BL, Bassard JE. Plasticity of specialized metabolism as mediated by dynamic metabolons. TRENDS IN PLANT SCIENCE 2015; 20:20-32. [PMID: 25435320 DOI: 10.1016/j.tplants.2014.11.002] [Citation(s) in RCA: 72] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2014] [Revised: 10/24/2014] [Accepted: 11/07/2014] [Indexed: 05/02/2023]
Abstract
The formation of specialized metabolites enables plants to respond to biotic and abiotic stresses, but requires the sequential action of multiple enzymes. To facilitate swift production and to avoid leakage of potentially toxic and labile intermediates, many of the biosynthetic pathways are thought to organize in multienzyme clusters termed metabolons. Dynamic assembly and disassembly enable the plant to rapidly switch the product profile and thereby prioritize its resources. The lifetime of metabolons is largely unknown mainly due to technological limitations. This review focuses on the factors that facilitate and stimulate the dynamic assembly of metabolons, including microenvironments, noncatalytic proteins, and allosteric regulation. Understanding how plants organize carbon fluxes within their metabolic grids would enable targeted bioengineering of high-value specialized metabolites.
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Affiliation(s)
- Tomas Laursen
- VILLUM Research Center for Plant Plasticity, Center for Synthetic Biology 'bioSYNergy', and Plant Biochemistry Laboratory, Department of Plant and Environmental Sciences, University of Copenhagen, 40 Thorvaldsensvej, DK-1871 Frederiksberg C, Copenhagen, Denmark
| | - Birger Lindberg Møller
- VILLUM Research Center for Plant Plasticity, Center for Synthetic Biology 'bioSYNergy', and Plant Biochemistry Laboratory, Department of Plant and Environmental Sciences, University of Copenhagen, 40 Thorvaldsensvej, DK-1871 Frederiksberg C, Copenhagen, Denmark; Carlsberg Laboratory, 10 Gamle Carlsberg Vej, DK-1799 Copenhagen V, Denmark.
| | - Jean-Etienne Bassard
- VILLUM Research Center for Plant Plasticity, Center for Synthetic Biology 'bioSYNergy', and Plant Biochemistry Laboratory, Department of Plant and Environmental Sciences, University of Copenhagen, 40 Thorvaldsensvej, DK-1871 Frederiksberg C, Copenhagen, Denmark
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28
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Leferink NGH, Hay S, Rigby SEJ, Scrutton NS. Towards the free energy landscape for catalysis in mammalian nitric oxide synthases. FEBS J 2014; 282:3016-29. [PMID: 25491181 DOI: 10.1111/febs.13171] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2014] [Revised: 12/05/2014] [Accepted: 12/05/2014] [Indexed: 01/30/2023]
Abstract
The general requirement for conformational sampling in biological electron transfer reactions catalysed by multi-domain redox systems has been emphasized in recent years. Crucially, we lack insight into the extent of the conformational space explored and the nature of the energy landscapes associated with these reactions. The nitric oxide synthases (NOS) produce the signalling molecule NO through a series of complex electron transfer reactions. There is accumulating evidence that protein domain dynamics and calmodulin binding are implicated in regulating electron flow from NADPH, through the FAD and FMN cofactors, to the haem oxygenase domain, where NO is generated. Simple models based on static crystal structures of the isolated reductase domain have suggested a role for large-scale motions of the FMN-binding domain in shuttling electrons from the reductase domain to the oxygenase domain. However, detailed insight into the higher-order domain architecture and dynamic structural transitions in NOS enzymes during enzyme turnover is lacking. In this review, we discuss the recent advances made towards mapping the catalytic free energy landscapes of NOS enzymes through integration of both structural techniques (e.g. cryo-electron microscopy) and biophysical techniques (e.g. pulsed-electron paramagnetic resonance). The general picture that emerges from these experiments is that NOS enzymes exist in an equilibrium of conformations, comprising a 'rugged' or 'frustrated' energy landscape, with a key regulatory role for calmodulin in driving vectorial electron transfer by altering the conformational equilibrium. A detailed understanding of these landscapes may provide new opportunities for discovery of isoform-specific inhibitors that bind at the dynamic interfaces of these multi-dimensional energy landscapes.
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Affiliation(s)
- Nicole G H Leferink
- Manchester Institute of Biotechnology and Faculty of Life Sciences, The University of Manchester, UK
| | - Sam Hay
- Manchester Institute of Biotechnology and Faculty of Life Sciences, The University of Manchester, UK
| | - Stephen E J Rigby
- Manchester Institute of Biotechnology and Faculty of Life Sciences, The University of Manchester, UK
| | - Nigel S Scrutton
- Manchester Institute of Biotechnology and Faculty of Life Sciences, The University of Manchester, UK
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29
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Huang R, Zhang M, Rwere F, Waskell L, Ramamoorthy A. Kinetic and structural characterization of the interaction between the FMN binding domain of cytochrome P450 reductase and cytochrome c. J Biol Chem 2014; 290:4843-4855. [PMID: 25512382 DOI: 10.1074/jbc.m114.582700] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Cytochrome P450 reductase (CPR) is a diflavin enzyme that transfers electrons to many protein partners. Electron transfer from CPR to cyt c has been extensively used as a model reaction to assess the redox activity of CPR. CPR is composed of multiple domains, among which the FMN binding domain (FBD) is the direct electron donor to cyt c. Here, electron transfer and complex formation between FBD and cyt c are investigated. Electron transfer from FBD to cyt c occurs at distinct rates that are dependent on the redox states of FBD. When compared with full-length CPR, FBD reduces cyt c at a higher rate in both the semiquinone and hydroquinone states. The NMR titration experiments reveal the formation of dynamic complexes between FBD and cyt c on a fast exchange time scale. Chemical shift mapping identified residues of FBD involved in the binding interface with cyt c, most of which are located in proximity to the solvent-exposed edge of the FMN cofactor along with other residues distributed around the surface of FBD. The structural model of the FBD-cyt c complex indicates two possible orientations of complex formation. The major complex structure shows a salt bridge formation between Glu-213/Glu-214 of FBD and Lys-87 of cyt c, which may be essential for the formation of the complex, and a predicted electron transfer pathway mediated by Lys-13 of cyt c. The findings provide insights into the function of CPR and CPR-cyt c interaction on a structural basis.
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Affiliation(s)
- Rui Huang
- Department of Chemistry and Biophysics, University of Michigan, Ann Arbor, Michigan 48109-1055 and
| | - Meng Zhang
- Department of Chemistry and Biophysics, University of Michigan, Ann Arbor, Michigan 48109-1055 and
| | - Freeborn Rwere
- Department of Anesthesiology, University of Michigan and Veterans Affairs Medical Center, Ann Arbor, Michigan 48105
| | - Lucy Waskell
- Department of Anesthesiology, University of Michigan and Veterans Affairs Medical Center, Ann Arbor, Michigan 48105
| | - Ayyalusamy Ramamoorthy
- Department of Chemistry and Biophysics, University of Michigan, Ann Arbor, Michigan 48109-1055 and.
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30
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Haque MM, Bayachou M, Tejero J, Kenney CT, Pearl NM, Im SC, Waskell L, Stuehr DJ. Distinct conformational behaviors of four mammalian dual-flavin reductases (cytochrome P450 reductase, methionine synthase reductase, neuronal nitric oxide synthase, endothelial nitric oxide synthase) determine their unique catalytic profiles. FEBS J 2014; 281:5325-40. [PMID: 25265015 DOI: 10.1111/febs.13073] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2014] [Revised: 08/27/2014] [Accepted: 09/25/2014] [Indexed: 12/14/2022]
Abstract
Multidomain enzymes often rely on large conformational motions to function. However, the conformational setpoints, rates of domain motions and relationships between these parameters and catalytic activity are not well understood. To address this, we determined and compared the conformational setpoints and the rates of conformational switching between closed unreactive and open reactive states in four mammalian diflavin NADPH oxidoreductases that catalyze important biological electron transfer reactions: cytochrome P450 reductase, methionine synthase reductase and endothelial and neuronal nitric oxide synthase. We used stopped-flow spectroscopy, single turnover methods and a kinetic model that relates electron flux through each enzyme to its conformational setpoint and its rates of conformational switching. The results show that the four flavoproteins, when fully-reduced, have a broad range of conformational setpoints (from 12% to 72% open state) and also vary 100-fold with respect to their rates of conformational switching between unreactive closed and reactive open states (cytochrome P450 reductase > neuronal nitric oxide synthase > methionine synthase reductase > endothelial nitric oxide synthase). Furthermore, simulations of the kinetic model could explain how each flavoprotein can support its given rate of electron flux (cytochrome c reductase activity) based on its unique conformational setpoint and switching rates. The present study is the first to quantify these conformational parameters among the diflavin enzymes and suggests how the parameters might be manipulated to speed or slow biological electron flux.
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Affiliation(s)
- Mohammad M Haque
- Department of Pathobiology, Lerner Research Institute, The Cleveland Clinic, Cleveland, OH, USA
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31
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Stiborová M, Bárta F, Levová K, Hodek P, Frei E, Arlt VM, Schmeiser HH. The influence of ochratoxin A on DNA adduct formation by the carcinogen aristolochic acid in rats. Arch Toxicol 2014; 89:2141-58. [PMID: 25209566 DOI: 10.1007/s00204-014-1360-1] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2014] [Accepted: 08/28/2014] [Indexed: 11/28/2022]
Abstract
UNLABELLED Exposure to the plant nephrotoxin and carcinogen aristolochic acid (AA) leads to the development of AA nephropathy, Balkan endemic nephropathy (BEN) and upper urothelial carcinoma (UUC) in humans. Beside AA, exposure to ochratoxin A (OTA) was linked to BEN. Although OTA was rejected as a factor for BEN/UUC, there is still no information whether the development of AA-induced BEN/UUC is influenced by OTA exposure. Therefore, we studied the influence of OTA on the genotoxicity of AA (AA-DNA adduct formation) in vivo. AA-DNA adducts were formed in liver and kidney of rats treated with AA or AA combined with OTA, but no OTA-related DNA adducts were detectable in rats treated with OTA alone or OTA combined with AA. Compared to rats treated with AA alone, AA-DNA adduct levels were 5.4- and 1.6-fold higher in liver and kidney, respectively, of rats treated with AA combined with OTA. Although AA and OTA induced NAD(P)H quinone oxidoreductase (NQO1) activating AA to DNA adducts, their combined treatment did not lead to either higher NQO1 enzyme activity or higher AA-DNA adduct levels in ex vivo incubations. Oxidation of AA I (8-methoxy-6-nitrophenanthro[3,4-d]-1,3-dioxole-5-carboxylic acid) to its detoxification metabolite, 8-hydroxyaristolochic acid, was lower in microsomes from rats treated with AA and OTA, and this was paralleled by lower activities of cytochromes P450 1A1/2 and/or 2C11 in these microsomes. Our results indicate that a decrease in AA detoxification after combined exposure to AA and OTA leads to an increase in AA-DNA adduct formation in liver and kidney of rats.
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Affiliation(s)
- Marie Stiborová
- Department of Biochemistry, Faculty of Science, Charles University, Albertov 2030, 128 40, Prague 2, Czech Republic.
| | - František Bárta
- Department of Biochemistry, Faculty of Science, Charles University, Albertov 2030, 128 40, Prague 2, Czech Republic
| | - Kateřina Levová
- Department of Biochemistry, Faculty of Science, Charles University, Albertov 2030, 128 40, Prague 2, Czech Republic
| | - Petr Hodek
- Department of Biochemistry, Faculty of Science, Charles University, Albertov 2030, 128 40, Prague 2, Czech Republic
| | - Eva Frei
- Division of Preventive Oncology, National Center for Tumor Diseases, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120, Heidelberg, Germany
| | - Volker M Arlt
- Analytical and Environmental Sciences Division, MRC-PHE Centre for Environmental and Health, King's College London, 150 Stamford Street, London, SE1 9NH, UK
| | - Heinz H Schmeiser
- Division of Radiopharmaceutical Chemistry (E030), German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120, Heidelberg, Germany
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32
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Smith CI, Convery JH, Harrison P, Khara B, Scrutton NS, Weightman P. Conformational change in cytochrome P450 reductase adsorbed at a Au(110)-phosphate buffer interface induced by interaction with nicotinamide adenine dinucleotide phosphate. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2014; 90:022708. [PMID: 25215759 DOI: 10.1103/physreve.90.022708] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/09/2014] [Indexed: 06/03/2023]
Abstract
Changes observed in the reflection anisotropy spectroscopy (RAS) profiles of monolayers of cytochrome P450 reductase adsorbed at Au(110)-electrolyte interfaces at 0.056 V following the addition of nicotinamide adenine dinucleotide phosphate (NADP(+)) are explained in terms of a simple model as arising from changes in the orientation of an isoalloxazine ring located in the flavin mononucleotide binding domain of the protein. The model also accounts for the changes observed in the RAS as the potential applied to the Au(110) surface is varied and suggests that differences in the dependence of the RAS profile of the adsorbed protein on the potential applied to the electrode in the absence and presence of NADP(+) are explicable as arising from a competition between the applied potential acting to reduce the protein and the NADP(+) to oxidize it.
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Affiliation(s)
- C I Smith
- Department of Physics, Oliver Lodge Laboratory, University of Liverpool, Liverpool, L69 7ZE, United Kingdom
| | - J H Convery
- Department of Physics, Oliver Lodge Laboratory, University of Liverpool, Liverpool, L69 7ZE, United Kingdom
| | - P Harrison
- Department of Physics, Oliver Lodge Laboratory, University of Liverpool, Liverpool, L69 7ZE, United Kingdom
| | - B Khara
- Faculty of Life Sciences, University of Manchester, Manchester Institute of Biotechnology, 131 Princess Street, Manchester, M1 7DN, United Kingdom
| | - N S Scrutton
- Faculty of Life Sciences, University of Manchester, Manchester Institute of Biotechnology, 131 Princess Street, Manchester, M1 7DN, United Kingdom
| | - P Weightman
- Department of Physics, Oliver Lodge Laboratory, University of Liverpool, Liverpool, L69 7ZE, United Kingdom
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33
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Stiborová M, Levová K, Bárta F, Šulc M, Frei E, Arlt VM, Schmeiser HH. The influence of dicoumarol on the bioactivation of the carcinogen aristolochic acid I in rats. Mutagenesis 2014; 29:189-200. [PMID: 24598128 DOI: 10.1093/mutage/geu004] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Aristolochic acid I (AAI) is the major toxic component of the plant extract AA, which leads to the development of nephropathy and urothelial cancer in human. Individual susceptibility to AAI-induced disease might reflect variability in enzymes that metabolise AAI. In vitro NAD(P)H quinone oxidoreductase (NQO1) is the most potent enzyme that activates AAI by catalyzing formation of AAI-DNA adducts, which are found in kidneys of patients exposed to AAI. Inhibition of renal NQO1 activity by dicoumarol has been shown in mice. Here, we studied the influence of dicoumarol on metabolic activation of AAI in Wistar rats in vivo. In contrast to previous in vitro findings, dicoumarol did not inhibit AAI-DNA adduct formation in rats. Compared with rats treated with AAI alone, 11- and 5.4-fold higher AAI-DNA adduct levels were detected in liver and kidney, respectively, of rats pretreated with dicoumarol prior to exposure to AAI. Cytosols and microsomes isolated from liver and kidney of these rats were analysed for activity and protein levels of enzymes known to be involved in AAI metabolism. The combination of dicoumarol with AAI induced NQO1 protein level and activity in both organs. This was paralleled by an increase in AAI-DNA adduct levels found in ex vivo incubations with cytosols from rats pretreated with dicoumarol compared to cytosols from untreated rats. Microsomal ex vivo incubations showed a lower AAI detoxication to its oxidative metabolite, 8-hydroxyaristolochic acid (AAIa), although cytochrome P450 (CYP) 1A was practically unchanged. Because of these unexpected results, we examined CYP2C activity in microsomes and found that treatment of rats with dicoumarol alone and in combination with AAI inhibited CYP2C6/11 in liver. Therefore, these results indicate that CYP2C enzymes might contribute to AAI detoxication.
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Affiliation(s)
- Marie Stiborová
- Department of Biochemistry, Faculty of Science, Charles University, Albertov 2030, 128 40 Prague 2, Czech Republic
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34
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Laursen T, Singha A, Rantzau N, Tutkus M, Borch J, Hedegård P, Stamou D, Møller BL, Hatzakis NS. Single molecule activity measurements of cytochrome P450 oxidoreductase reveal the existence of two discrete functional states. ACS Chem Biol 2014; 9:630-4. [PMID: 24359083 DOI: 10.1021/cb400708v] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Electron transfer between membrane spanning oxidoreductase enzymes controls vital metabolic processes. Here we studied for the first time with single molecule resolution the function of P450 oxidoreductase (POR), the canonical membrane spanning activator of all microsomal cytochrome P450 enzymes. Measurements and statistical analysis of individual catalytic turnover cycles shows POR to sample at least two major functional states. This phenotype may underlie regulatory interactions with different cytochromes P450 but to date has remained masked in bulk kinetics. To ensure that we measured the inherent behavior of POR, we reconstituted the full length POR in "native like" membrane patches, nanodiscs. Nanodisc reconstitution increased stability by ∼2-fold as compared to detergent solubilized POR and showed significantly increased activity at biologically relevant ionic strength conditions, highlighting the importance of studying POR function in a membrane environment. This assay paves the way for studying the function of additional membrane spanning oxidoreductases with single molecule resolution.
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Affiliation(s)
- Tomas Laursen
- Plant
Biochemistry Laboratory, Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsenvej 40, DK-1871 Frederiksberg C, Denmark
- bioSYNergy,
Center for Synthetic Biology, University of Copenhagen, Denmark
| | - Aparajita Singha
- Bio-Nanotechnology
Laboratory, Department of Chemistry, Nano-Science Center, Lundbeck
Foundation Center Biomembranes in Nanomedicine, University of Copenhagen, 2100 Copenhagen, Denmark
- bioSYNergy,
Center for Synthetic Biology, University of Copenhagen, Denmark
| | - Nicolai Rantzau
- Bio-Nanotechnology
Laboratory, Department of Chemistry, Nano-Science Center, Lundbeck
Foundation Center Biomembranes in Nanomedicine, University of Copenhagen, 2100 Copenhagen, Denmark
- bioSYNergy,
Center for Synthetic Biology, University of Copenhagen, Denmark
| | - Marijonas Tutkus
- Bio-Nanotechnology
Laboratory, Department of Chemistry, Nano-Science Center, Lundbeck
Foundation Center Biomembranes in Nanomedicine, University of Copenhagen, 2100 Copenhagen, Denmark
- bioSYNergy,
Center for Synthetic Biology, University of Copenhagen, Denmark
| | - Jonas Borch
- Department
of Biochemistry and Molecular Biology, University of Southern Denmark, DK−5230 Odense M, Denmark
| | - Per Hedegård
- Nano-Science
Center, Niels Bohr Institute, University of Copenhagen, Denmark
| | - Dimitrios Stamou
- Bio-Nanotechnology
Laboratory, Department of Chemistry, Nano-Science Center, Lundbeck
Foundation Center Biomembranes in Nanomedicine, University of Copenhagen, 2100 Copenhagen, Denmark
- bioSYNergy,
Center for Synthetic Biology, University of Copenhagen, Denmark
| | - Birger Lindberg Møller
- Plant
Biochemistry Laboratory, Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsenvej 40, DK-1871 Frederiksberg C, Denmark
- bioSYNergy,
Center for Synthetic Biology, University of Copenhagen, Denmark
| | - Nikos S. Hatzakis
- Bio-Nanotechnology
Laboratory, Department of Chemistry, Nano-Science Center, Lundbeck
Foundation Center Biomembranes in Nanomedicine, University of Copenhagen, 2100 Copenhagen, Denmark
- bioSYNergy,
Center for Synthetic Biology, University of Copenhagen, Denmark
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35
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Sobolewska-Stawiarz A, Leferink NGH, Fisher K, Heyes DJ, Hay S, Rigby SEJ, Scrutton NS. Energy landscapes and catalysis in nitric-oxide synthase. J Biol Chem 2014; 289:11725-11738. [PMID: 24610812 PMCID: PMC4002082 DOI: 10.1074/jbc.m114.548834] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Nitric oxide (NO) plays diverse roles in mammalian physiology. It is involved in blood pressure regulation, neurotransmission, and immune response, and is generated through complex electron transfer reactions catalyzed by NO synthases (NOS). In neuronal NOS (nNOS), protein domain dynamics and calmodulin binding are implicated in regulating electron flow from NADPH, through the FAD and FMN cofactors, to the heme oxygenase domain, the site of NO generation. Simple models based on crystal structures of nNOS reductase have invoked a role for large scale motions of the FMN-binding domain in shuttling electrons from the FAD-binding domain to the heme oxygenase domain. However, molecular level insight of the dynamic structural transitions in NOS enzymes during enzyme catalysis is lacking. We use pulsed electron-electron double resonance spectroscopy to derive inter-domain distance relationships in multiple conformational states of nNOS. These distance relationships are correlated with enzymatic activity through variable pressure kinetic studies of electron transfer and turnover. The binding of NADPH and calmodulin are shown to influence interdomain distance relationships as well as reaction chemistry. An important effect of calmodulin binding is to suppress adventitious electron transfer from nNOS to molecular oxygen and thereby preventing accumulation of reactive oxygen species. A complex landscape of conformations is required for nNOS catalysis beyond the simple models derived from static crystal structures of nNOS reductase. Detailed understanding of this landscape advances our understanding of nNOS catalysis/electron transfer, and could provide new opportunities for the discovery of small molecule inhibitors that bind at dynamic protein interfaces of this multidimensional energy landscape.
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Affiliation(s)
- Anna Sobolewska-Stawiarz
- From the Manchester Institute of Biotechnology and Faculty of Life Sciences, University of Manchester, Manchester M1 7DN, United Kingdom
| | - Nicole G H Leferink
- From the Manchester Institute of Biotechnology and Faculty of Life Sciences, University of Manchester, Manchester M1 7DN, United Kingdom
| | - Karl Fisher
- From the Manchester Institute of Biotechnology and Faculty of Life Sciences, University of Manchester, Manchester M1 7DN, United Kingdom
| | - Derren J Heyes
- From the Manchester Institute of Biotechnology and Faculty of Life Sciences, University of Manchester, Manchester M1 7DN, United Kingdom
| | - Sam Hay
- From the Manchester Institute of Biotechnology and Faculty of Life Sciences, University of Manchester, Manchester M1 7DN, United Kingdom
| | - Stephen E J Rigby
- From the Manchester Institute of Biotechnology and Faculty of Life Sciences, University of Manchester, Manchester M1 7DN, United Kingdom
| | - Nigel S Scrutton
- From the Manchester Institute of Biotechnology and Faculty of Life Sciences, University of Manchester, Manchester M1 7DN, United Kingdom.
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36
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Meints CE, Parke SM, Wolthers KR. Proximal FAD histidine residue influences interflavin electron transfer in cytochrome P450 reductase and methionine synthase reductase. Arch Biochem Biophys 2014; 547:18-26. [PMID: 24589657 DOI: 10.1016/j.abb.2014.02.009] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2014] [Revised: 02/17/2014] [Accepted: 02/19/2014] [Indexed: 10/25/2022]
Abstract
Cytochrome P450 reductase (CPR) and methionine synthase reductase (MSR) transfer reducing equivalents from NADPH to FAD to FMN. In CPR, hydride transfer and interflavin electron transfer are kinetically coupled steps, but in MSR the two catalytic steps are represented by two distinct kinetic phases leading to transient formation of the FAD hydroquinone. In human CPR, His(322) forms a hydrogen-bond with the highly conserved Asp(677), a member of the catalytic triad. The catalytic triad is present in MSR, but Ala(312) replaces the histidine residue. To examine if this structural variation accounts for differences in their kinetic behavior, reciprocal substitutions were created. Substitution of His(322) for Ala in CPR does not affect the rate of NADPH hydride transfer or the FAD redox potentials, but does impede interflavin electron transfer. For MSR, swapping Ala(312) for a histidine residue resulted in the kinetic coupling of hydride and interflavin electron transfer, and eliminated the formation of the FAD hydroquinone intermediate. For both enzymes, placement of the His residue in the active site weakens coenzyme binding affinity. The data suggest that the proximal FAD histidine residue accelerates proton-coupled electron transfer from FADH2 to the higher potential FMN; a mechanism for this catalytic role is discussed.
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Affiliation(s)
- Carla E Meints
- Department of Chemistry, University of British Columbia Okanagan, 3333 University Way, Kelowna, BC V1V 1V7, Canada
| | - Sarah M Parke
- Department of Chemistry, University of British Columbia Okanagan, 3333 University Way, Kelowna, BC V1V 1V7, Canada
| | - Kirsten R Wolthers
- Department of Chemistry, University of British Columbia Okanagan, 3333 University Way, Kelowna, BC V1V 1V7, Canada.
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Huang WC, Ellis J, Moody P, Raven E, Roberts G. Redox-linked domain movements in the catalytic cycle of cytochrome p450 reductase. Structure 2013; 21:1581-9. [PMID: 23911089 PMCID: PMC3763376 DOI: 10.1016/j.str.2013.06.022] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2013] [Revised: 06/24/2013] [Accepted: 06/26/2013] [Indexed: 11/17/2022]
Abstract
NADPH-cytochrome P450 reductase is a key component of the P450 mono-oxygenase drug-metabolizing system. There is evidence for a conformational equilibrium involving large-scale domain motions in this enzyme. We now show, using small-angle X-ray scattering (SAXS) and small-angle neutron scattering, that delivery of two electrons to cytochrome P450 reductase leads to a shift in this equilibrium from a compact form, similar to the crystal structure, toward an extended form, while coenzyme binding favors the compact form. We present a model for the extended form of the enzyme based on nuclear magnetic resonance and SAXS data. Using the effects of changes in solution conditions and of site-directed mutagenesis, we demonstrate that the conversion to the extended form leads to an enhanced ability to transfer electrons to cytochrome c. This structural evidence shows that domain motion is linked closely to the individual steps of the catalytic cycle of cytochrome P450 reductase, and we propose a mechanism for this.
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Affiliation(s)
- Wei-Cheng Huang
- Henry Wellcome Laboratories for Structural Biology, Department of Biochemistry, University of Leicester, Henry Wellcome Building, Leicester LE1 9HN, UK
| | - Jacqueline Ellis
- Henry Wellcome Laboratories for Structural Biology, Department of Biochemistry, University of Leicester, Henry Wellcome Building, Leicester LE1 9HN, UK
| | - Peter C.E. Moody
- Henry Wellcome Laboratories for Structural Biology, Department of Biochemistry, University of Leicester, Henry Wellcome Building, Leicester LE1 9HN, UK
| | - Emma L. Raven
- Department of Chemistry, University of Leicester, Leicester LE1 7RH, UK
| | - Gordon C.K. Roberts
- Henry Wellcome Laboratories for Structural Biology, Department of Biochemistry, University of Leicester, Henry Wellcome Building, Leicester LE1 9HN, UK
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38
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Lu Z, Ma G, Veinot JGC, Wong CS. Disruption of biomolecule function by nanoparticles: how do gold nanoparticles affect Phase I biotransformation of persistent organic pollutants? CHEMOSPHERE 2013; 93:123-32. [PMID: 23763865 DOI: 10.1016/j.chemosphere.2013.05.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2013] [Revised: 04/23/2013] [Accepted: 05/02/2013] [Indexed: 05/22/2023]
Abstract
The potential influence of nanoparticles on cytochrome P-450 (CYP) isozyme mediated Phase I biotransformation of persistent organic pollutants (POPs) in vitro was investigated using citrate-capped gold nanoparticles (AuNPs) and 2,2',3,5',6-pentachlorobiphenyl (PCB 95) as the probe nanoparticle and compound, respectively. AuNPs affected the biotransformation activity of rat CYP2B1 and changed the atropisomeric composition of PCB 95, depending on the incubation time and the AuNP concentration. Electrostatic repulsion between citrate-coated AuNPs and rat CYP2B1 may influence the active conformation of the isozyme and consequently affect its activity and stereoselectivity. In addition, the effects of AuNPs on rat CYP2B1 activity also appeared to be through interference with the CYP catalytic cycle's electron transfer chain. Incubations with AuNPs had a decline in buffer conductance and an absorbance band red shift of AuNPs, from electrostatic interactions of K(+) with negatively-charged AuNP aggregates. These ionic strength changes affected the formation rate of nicotinamide adenine dinucleotide phosphate, which provides electrons for the oxidative reaction cycle, and the biotransformation activity and stereoselectivity of CYP. This study suggests that charged nanoparticles may be able to alter the functions of biomolecules directly, by electrostatic interaction, or indirectly, by changes to the surrounding ionic strength. These factors should be taken into account for further understanding and prediction of the environmental behavior and fate of POPs and nanoparticles.
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Affiliation(s)
- Zhe Lu
- Department of Chemistry, University of Manitoba, Winnipeg, MB, Canada R3T 2N2
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39
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Weightman P, Smith CI, Convery JH, Harrison P, Khara B, Scrutton NS. Conformational change induced by electron transfer in a monolayer of cytochrome P450 reductase adsorbed at the Au(110)-phosphate buffer interface. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2013; 88:032715. [PMID: 24125302 DOI: 10.1103/physreve.88.032715] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2013] [Indexed: 06/02/2023]
Abstract
The reflection anisotropy spectroscopy profiles of a variant of cytochrome P450 reductase adsorbed at the Au(110)-phosphate buffer interface depend on the sequence of potentials applied to the Au(110) electrode. It is suggested that this dependence arises from changes in the orientation of the isoalloxazine ring structures in the protein with respect to the Au(110) surface. This offers a method of monitoring conformational change in this protein by measuring variations in the reflection anisotropy spectrum arising from changes in the redox potential.
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Affiliation(s)
- P Weightman
- Department of Physics, Oliver Lodge Laboratory, University of Liverpool, Liverpool L69 7ZE, United Kingdom
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40
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Sündermann A, Oostenbrink C. Molecular dynamics simulations give insight into the conformational change, complex formation, and electron transfer pathway for cytochrome P450 reductase. Protein Sci 2013; 22:1183-95. [PMID: 23832577 DOI: 10.1002/pro.2307] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2013] [Revised: 06/07/2013] [Accepted: 06/25/2013] [Indexed: 02/02/2023]
Abstract
Cytochrome P450 reductase (CYPOR) undergoes a large conformational change to allow for an electron transfer to a redox partner to take place. After an internal electron transfer over its cofactors, it opens up to facilitate the interaction and electron transfer with a cytochrome P450. The open conformation appears difficult to crystallize. Therefore, a model of a human CYPOR in the open conformation was constructed to be able to investigate the stability and conformational change of this protein by means of molecular dynamics simulations. Since the role of the protein is to provide electrons to a redox partner, the interactions with cytochrome P450 2D6 (2D6) were investigated and a possible complex structure is suggested. Additionally, electron pathway calculations with a newly written program were performed to investigate which amino acids relay the electrons from the FMN cofactor of CYPOR to the HEME of 2D6. Several possible interacting amino acids in the complex, as well as a possible electron transfer pathway were identified and open the way for further investigation by site directed mutagenesis studies.
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Affiliation(s)
- Axel Sündermann
- Department of Material Sciences and Process Engineering, Institute of Molecular Modeling and Simulation, University of Natural Resources and Life Sciences Vienna, Muthgasse 18, A-1190, Vienna, Austria
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41
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Jett JE, Lederman D, Wollenberg LA, Li D, Flora DR, Bostick CD, Tracy TS, Gannett PM. Measurement of electron transfer through cytochrome P450 protein on nanopillars and the effect of bound substrates. J Am Chem Soc 2013; 135:3834-40. [PMID: 23427827 PMCID: PMC3876957 DOI: 10.1021/ja309104g] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Electron transfer in cytochrome P450 enzymes is a fundamental process for activity. It is difficult to measure electron transfer in these enzymes because under the conditions typically used they exist in a variety of states. Using nanotechnology-based techniques, gold conducting nanopillars were constructed in an indexed array. The P450 enzyme CYP2C9 was attached to each of these nanopillars, and conductivity measurements made using conducting probe atomic force microscopy under constant force conditions. The conductivity measurements were made on CYP2C9 alone and with bound substrates, a bound substrate-effector pair, and a bound inhibitor. Fitting of the data with the Poole-Frenkel model indicates a correlation between the barrier height for electron transfer and the ease of CYP2C9-mediated metabolism of the bound substrates, though the spin state of iron is not well correlated. The approach described here should have broad application to the measurement of electron transfer in P450 enzymes and other metalloenzymes.
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Affiliation(s)
- John E. Jett
- West Virginia University, Basic Pharmaceutical Sciences, Morgantown, WV 26506-9530
| | - David Lederman
- West Virginia University, Department of Physics, Morgantown, WV 26506-6315
| | - Lance A. Wollenberg
- West Virginia University, Basic Pharmaceutical Sciences, Morgantown, WV 26506-9530
| | - Debin Li
- West Virginia University, Department of Physics, Morgantown, WV 26506-6315
| | - Darcy R. Flora
- University of Minnesota, College of Pharmacy, Minneapolis, MN, 55455
| | | | - Timothy S. Tracy
- University of Kentucky, College of Pharmacy, Lexington, KY 40536
| | - Peter M. Gannett
- West Virginia University, Basic Pharmaceutical Sciences, Morgantown, WV 26506-9530
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42
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Iyanagi T, Xia C, Kim JJP. NADPH-cytochrome P450 oxidoreductase: prototypic member of the diflavin reductase family. Arch Biochem Biophys 2012; 528:72-89. [PMID: 22982532 PMCID: PMC3606592 DOI: 10.1016/j.abb.2012.09.002] [Citation(s) in RCA: 88] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2012] [Revised: 09/01/2012] [Accepted: 09/03/2012] [Indexed: 12/31/2022]
Abstract
NADPH-cytochrome P450 oxidoreductase (CYPOR) and nitric oxide synthase (NOS), two members of the diflavin oxidoreductase family, are multi-domain enzymes containing distinct FAD and FMN domains connected by a flexible hinge. FAD accepts a hydride ion from NADPH, and reduced FAD donates electrons to FMN, which in turn transfers electrons to the heme center of cytochrome P450 or NOS oxygenase domain. Structural analysis of CYPOR, the prototype of this enzyme family, has revealed the exact nature of the domain arrangement and the role of residues involved in cofactor binding. Recent structural and biophysical studies of CYPOR have shown that the two flavin domains undergo large domain movements during catalysis. NOS isoforms contain additional regulatory elements within the reductase domain that control electron transfer through Ca(2+)-dependent calmodulin (CaM) binding. The recent crystal structure of an iNOS Ca(2+)/CaM-FMN construct, containing the FMN domain in complex with Ca(2+)/CaM, provided structural information on the linkage between the reductase and oxgenase domains of NOS, making it possible to model the holo iNOS structure. This review summarizes recent advances in our understanding of the dynamics of domain movements during CYPOR catalysis and the role of the NOS diflavin reductase domain in the regulation of NOS isozyme activities.
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Affiliation(s)
- Takashi Iyanagi
- Department of Biochemistry, Medical College of Wisconsin, USA
- Department of Life Science, The Himeji Institute of Technology, University of Hyogo, Japan
| | - Chuanwu Xia
- Department of Biochemistry, Medical College of Wisconsin, USA
| | - Jung-Ja P. Kim
- Department of Biochemistry, Medical College of Wisconsin, USA
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43
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Abstract
Diflavin reductases are essential proteins capable of splitting the two-electron flux from reduced pyridine nucleotides to a variety of one electron acceptors. The primary sequence of diflavin reductases shows a conserved domain organization harboring two catalytic domains bound to the FAD and FMN flavins sandwiched by one or several non-catalytic domains. The catalytic domains are analogous to existing globular proteins: the FMN domain is analogous to flavodoxins while the FAD domain resembles ferredoxin reductases. The first structural determination of one member of the diflavin reductases family raised some questions about the architecture of the enzyme during catalysis: both FMN and FAD were in perfect position for interflavin transfers but the steric hindrance of the FAD domain rapidly prompted more complex hypotheses on the possible mechanisms for the electron transfer from FMN to external acceptors. Hypotheses of domain reorganization during catalysis in the context of the different members of this family were given by many groups during the past twenty years. This review will address the recent advances in various structural approaches that have highlighted specific dynamic features of diflavin reductases.
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Affiliation(s)
- Louise Aigrain
- Gene Machines Group, Clarendon Laboratory, Department of Physics, University of Oxford, Parks Road, Oxford OX1 3PU, UK; E-Mail:
| | - Fataneh Fatemi
- Institut de Chimie des Substances Naturelles, CNRS, UPR 2301, Centre de Recherche de Gif, 1 Av. de la Terrasse, 91198 Gif-sur-Yvette Cedex, France; E-Mails: (F.F.); (O.F.); (E.L.)
| | - Oriane Frances
- Institut de Chimie des Substances Naturelles, CNRS, UPR 2301, Centre de Recherche de Gif, 1 Av. de la Terrasse, 91198 Gif-sur-Yvette Cedex, France; E-Mails: (F.F.); (O.F.); (E.L.)
| | - Ewen Lescop
- Institut de Chimie des Substances Naturelles, CNRS, UPR 2301, Centre de Recherche de Gif, 1 Av. de la Terrasse, 91198 Gif-sur-Yvette Cedex, France; E-Mails: (F.F.); (O.F.); (E.L.)
| | - Gilles Truan
- Université de Toulouse; INSA, UPS, INP; LISBP, 135 Avenue de Rangueil, F-31077 Toulouse, France
- INRA, UMR792 Ingénierie des Systèmes Biologiques et des Procédés, F-31400 Toulouse, France
- CNRS, UMR5504, F-31400 Toulouse, France
- Author to whom correspondence should be addressed; E-Mail: ; Tel.: +33-567048813; Fax: +33-567048814
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44
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Biswas D, Pandya V, Singh AK, Mondal AK, Kumaran S. Co-factor binding confers substrate specificity to xylose reductase from Debaryomyces hansenii. PLoS One 2012; 7:e45525. [PMID: 23049810 PMCID: PMC3458928 DOI: 10.1371/journal.pone.0045525] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2012] [Accepted: 08/21/2012] [Indexed: 01/07/2023] Open
Abstract
Binding of substrates into the active site, often through complementarity of shapes and charges, is central to the specificity of an enzyme. In many cases, substrate binding induces conformational changes in the active site, promoting specific interactions between them. In contrast, non-substrates either fail to bind or do not induce the requisite conformational changes upon binding and thus no catalysis occurs. In principle, both lock and key and induced-fit binding can provide specific interactions between the substrate and the enzyme. In this study, we present an interesting case where cofactor binding pre-tunes the active site geometry to recognize only the cognate substrates. We illustrate this principle by studying the substrate binding and kinetic properties of Xylose Reductase from Debaryomyces hansenii (DhXR), an AKR family enzyme which catalyzes the reduction of carbonyl substrates using NADPH as co-factor. DhXR reduces D-xylose with increased specificity and shows no activity towards "non-substrate" sugars like L-rhamnose. Interestingly, apo-DhXR binds to D-xylose and L-rhamnose with similar affinity (K(d)∼5.0-10.0 mM). Crystal structure of apo-DhXR-rhamnose complex shows that L-rhamnose is bound to the active site cavity. L-rhamnose does not bind to holo-DhXR complex and thus, it cannot competitively inhibit D-xylose binding and catalysis even at 4-5 fold molar excess. Comparison of K(d) values with K(m) values reveals that increased specificity for D-xylose is achieved at the cost of moderately reduced affinity. The present work reveals a latent regulatory role for cofactor binding which was previously unknown and suggests that cofactor induced conformational changes may increase the complimentarity between D-xylose and active site similar to specificity achieved through induced-fit mechanism.
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Affiliation(s)
- Dipanwita Biswas
- Council of Scientific and Industrial Research (CSIR), Institute of Microbial Technology, Chandigarh, India
| | - Vaibhav Pandya
- Council of Scientific and Industrial Research (CSIR), Institute of Microbial Technology, Chandigarh, India
| | - Appu Kumar Singh
- Council of Scientific and Industrial Research (CSIR), Institute of Microbial Technology, Chandigarh, India
| | - Alok K. Mondal
- Council of Scientific and Industrial Research (CSIR), Institute of Microbial Technology, Chandigarh, India
| | - S. Kumaran
- Council of Scientific and Industrial Research (CSIR), Institute of Microbial Technology, Chandigarh, India
- * E-mail:
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45
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Convery JH, Smith CI, Khara B, Scrutton NS, Harrison P, Farrell T, Martin DS, Weightman P. Controlling the formation of a monolayer of cytochrome P450 reductase onto Au surfaces. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2012; 86:011903. [PMID: 23005448 DOI: 10.1103/physreve.86.011903] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2011] [Indexed: 06/01/2023]
Abstract
The conditions necessary for the formation of a monolayer and a bilayer of a mutated form (P499C) of human cytochrome P450 reductase on a Au(110)/electrolyte interface have been determined using a quartz crystal microbalance with dissipation, atomic force microscopy, and reflection anisotropy spectroscopy (RAS). The molecules adsorb through a Au-S linkage and, for the monolayer, adopt an ordered structure on the Au(110) substrate in which the optical axes of the dipoles contributing to the RAS signal are aligned roughly along the optical axes of the Au(110) substrate. Differences between the absorption spectrum of the molecules in a solution and the RAS profile of the adsorbed monolayer are attributed to surface order in the orientation of dipoles that contribute in the low energy region of the spectrum, a roughly vertical orientation on the surface of the long axes of the isoalloxazine rings and the lack of any preferred orientation in the molecular structure of the dipoles in the aromatic amino acids. Our studies establish an important proof of principle for immobilizing large biological macromolecules to gold surfaces. This opens up detailed studies of the dynamics of biological macromolecules by RAS, which have general applications in studies of biological redox chemistry that are coupled to protein dynamics.
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Affiliation(s)
- J H Convery
- Department of Physics, Oliver Lodge Laboratory, University of Liverpool, Liverpool L69 7ZE, United Kingdom
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46
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Pudney CR, Heyes DJ, Khara B, Hay S, Rigby SEJ, Scrutton NS. Kinetic and spectroscopic probes of motions and catalysis in the cytochrome P450 reductase family of enzymes. FEBS J 2012; 279:1534-44. [PMID: 22142452 DOI: 10.1111/j.1742-4658.2011.08442.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
There is a mounting body of evidence to suggest that enzyme motions are linked to function, although the design of informative experiments aiming to evaluate how this motion facilitates reaction chemistry is challenging. For the family of diflavin reductase enzymes, typified by cytochrome P450 reductase, accumulating evidence suggests that electron transfer is somehow coupled to large-scale conformational change and that protein motions gate the electron transfer chemistry. These ideas have emerged from a variety of experimental approaches, including structural biology methods (i.e. X-ray crystallography, electron paramagnetic/NMR spectroscopies and solution X-ray scattering) and advanced spectroscopic techniques that have employed the use of variable pressure kinetic methodologies, together with solvent perturbation studies (i.e. ionic strength, deuteration and viscosity). Here, we offer a personal perspective on the importance of motions to electron transfer in the cytochrome P450 reductase family of enzymes, drawing on the detailed insight that can be obtained by combining these multiple structural and biophysical approaches.
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Affiliation(s)
- Christopher R Pudney
- Manchester Interdisciplinary Biocentre, Faculty of Life Sciences, University of Manchester, Manchester, UK
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