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Reidelbach M, Zimmer C, Meunier B, Rich PR, Sharma V. Electron Transfer Coupled to Conformational Dynamics in Cell Respiration. Front Mol Biosci 2021; 8:711436. [PMID: 34422907 PMCID: PMC8378252 DOI: 10.3389/fmolb.2021.711436] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Accepted: 07/26/2021] [Indexed: 11/25/2022] Open
Abstract
Cellular respiration is a fundamental process required for energy production in many organisms. The terminal electron transfer complex in mitochondrial and many bacterial respiratory chains is cytochrome c oxidase (CcO). This converts the energy released in the cytochrome c/oxygen redox reaction into a transmembrane proton electrochemical gradient that is used subsequently to power ATP synthesis. Despite detailed knowledge of electron and proton transfer paths, a central question remains as to whether the coupling between electron and proton transfer in mammalian mitochondrial forms of CcO is mechanistically equivalent to its bacterial counterparts. Here, we focus on the conserved span between H376 and G384 of transmembrane helix (TMH) X of subunit I. This conformationally-dynamic section has been suggested to link the redox activity with the putative H pathway of proton transfer in mammalian CcO. The two helix X mutants, Val380Met (V380M) and Gly384Asp (G384D), generated in the genetically-tractable yeast CcO, resulted in a respiratory-deficient phenotype caused by the inhibition of intra-protein electron transfer and CcO turnover. Molecular aspects of these variants were studied by long timescale atomistic molecular dynamics simulations performed on wild-type and mutant bovine and yeast CcOs. We identified redox- and mutation-state dependent conformational changes in this span of TMH X of bovine and yeast CcOs which strongly suggests that this dynamic module plays a key role in optimizing intra-protein electron transfers.
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Affiliation(s)
- Marco Reidelbach
- Department of Physics, University of Helsinki, Helsinki, Finland
| | - Christoph Zimmer
- Department of Structural and Molecular Biology, University College London, London, United Kingdom
| | - Brigitte Meunier
- Institute for Integrative Biology of the Cell (I2BC), Université Paris-Saclay, Gif-sur-Yvette, France
| | - Peter R Rich
- Department of Structural and Molecular Biology, University College London, London, United Kingdom
| | - Vivek Sharma
- Department of Physics, University of Helsinki, Helsinki, Finland.,HiLIFE Institute of Biotechnology, University of Helsinki, Helsinki, Finland
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Zhang K, Chen Y, Huang X, Qu P, Pan Q, Lü L, Jiang S, Ren T, Su H. Expression and clinical significance of cytochrome c oxidase subunit IV in colorectal cancer patients. Arch Med Sci 2016; 12:68-77. [PMID: 26925120 PMCID: PMC4754367 DOI: 10.5114/aoms.2016.57581] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/16/2013] [Accepted: 02/18/2014] [Indexed: 01/12/2023] Open
Abstract
INTRODUCTION Previous studies have demonstrated that the expression of cytochrome c oxidase (COX) subunits encoded by mitochondrial DNA is elevated in colorectal cancer (CRC). However, the expression of nuclear DNA-encoded COX IV and its clinical significance have not yet been investigated in CRC. MATERIAL AND METHODS We examined COX IV expression in paired CRC samples (cancer and pericancerous tissues) by quantitative real-time polymerase chain reaction (qPCR), Western blot and immunohistochemical staining and analyzed its clinical significance. RESULTS qPCR and Western blot analyses showed that COX IV expression was significantly elevated at both the mRNA (p = 0.05) and protein levels in CRC tissue samples when compared with those in paired pericancerous tissues. Immunohistochemistry also revealed that COX IV expression was significantly increased in CRC tissues (p < 0.001). Association analyses showed that there was no significant association between COX IV expression and clinical parameters of CRC patients except for gender (p = 0.017). Moreover, we did not find any association between COX IV expression and overall survival or recurrence-free survival of CRC patients. Further analysis showed no significant relationship between the expression of COX IV and proliferating cell nuclear antigen (PCNA), a marker of cell proliferation. CONCLUSIONS Our findings suggest that elevated COX IV expression may play an important role in colorectal carcinogenesis, but not in progression, which warrants further investigation in future studies.
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Affiliation(s)
- Kun Zhang
- Department of Oncology, Tangdu Hospital, Fourth Military Medical University, Xi'an, China
| | - Yibing Chen
- State Key Laboratory of Cancer Biology and Experimental Teaching Center of Basic Medicine, Fourth Military Medical University, Xi'an, China
| | - Xiaojun Huang
- State Key Laboratory of Cancer Biology and Experimental Teaching Center of Basic Medicine, Fourth Military Medical University, Xi'an, China
| | - Ping Qu
- State Key Laboratory of Cancer Biology and Experimental Teaching Center of Basic Medicine, Fourth Military Medical University, Xi'an, China
| | - Qiuzhong Pan
- Department of Biotherapy, Sun Yat-Sen University Cancer Center, Guangdong, China
| | - Lin Lü
- Department of Biotherapy, Sun Yat-Sen University Cancer Center, Guangdong, China
| | - Shanshan Jiang
- Department of Biotherapy, Sun Yat-Sen University Cancer Center, Guangdong, China
| | - Tingitng Ren
- State Key Laboratory of Cancer Biology and Experimental Teaching Center of Basic Medicine, Fourth Military Medical University, Xi'an, China
| | - Haichuan Su
- Department of Oncology, Tangdu Hospital, Fourth Military Medical University, Xi'an, China
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Goyal P, Yang S, Cui Q. Microscopic basis for kinetic gating in Cytochrome c oxidase: insights from QM/MM analysis. Chem Sci 2015; 6:826-841. [PMID: 25678950 PMCID: PMC4321873 DOI: 10.1039/c4sc01674b] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Understanding the mechanism of vectorial proton pumping in biomolecules requires establishing the microscopic basis for the regulation of both thermodynamic and kinetic features of the relevant proton transfer steps.
Understanding the mechanism of vectorial proton pumping in biomolecules requires establishing the microscopic basis for the regulation of both thermodynamic and kinetic features of the relevant proton transfer steps. For the proton pump cytochrome c oxidase, while the regulation of thermodynamic driving force for key proton transfers has been discussed in great detail, the microscopic basis for the control of proton transfer kinetics has been poorly understood. Here we carry out extensive QM/MM free energy simulations to probe the kinetics of relevant proton transfer steps and analyze the effects of local structure and hydration level. We show that protonation of the proton loading site (PLS, taken to be a propionate of heme a3) requires a concerted process in which a key glutamic acid (Glu286H) delivers the proton to the PLS while being reprotonated by an excess proton coming from the D-channel. The concerted nature of the mechanism is a crucial feature that enables the loading of the PLS before the cavity containing Glu286 is better hydrated to lower its pKa to experimentally measured range; the charged rather than dipolar nature of the process also ensures a tight coupling with heme a reduction, as emphasized by Siegbahn and Blomberg. In addition, we find that rotational flexibility of the PLS allows its protonation before that of the binuclear center (the site where oxygen gets reduced to water). Together with our recent study (P. Goyal, et al., Proc. Natl. Acad. Sci. U. S. A., 2013, 110, 18886–18891) that focused on the modulation of Glu286 pKa, the current work suggests a mechanism that builds in a natural sequence for the protonation of the PLS prior to that of the binuclear center. This provides microscopic support to the kinetic constraints revealed by kinetic network analysis as essential elements that ensure an efficient vectorial proton transport in cytochrome c oxidase.
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Affiliation(s)
- Puja Goyal
- Department of Chemistry and Theoretical Chemistry Institute, University of Wisconsin-Madison, 1101 University Avenue, Madison, WI 53706
| | - Shuo Yang
- Department of Chemistry and Theoretical Chemistry Institute, University of Wisconsin-Madison, 1101 University Avenue, Madison, WI 53706
| | - Qiang Cui
- Department of Chemistry and Theoretical Chemistry Institute, University of Wisconsin-Madison, 1101 University Avenue, Madison, WI 53706
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LE PH, Huang SC, Lim SN, Chou CH, Yeh TS, Chen TC, Yen TH, Su MY, Chiu CT, Yeh CT, Lin WR. Complex IV subunit 1 defect predicts postoperative survival in hepatocellular carcinoma. Oncol Lett 2014; 7:1430-1438. [PMID: 24765151 PMCID: PMC3997697 DOI: 10.3892/ol.2014.1966] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2013] [Accepted: 02/20/2014] [Indexed: 02/07/2023] Open
Abstract
Mitochondrial oxidative phosphorylation (OXPHOS) is responsible for adenosine triphosphate synthesis and OXPHOS deficiency plays a significant role in tumorigenesis. The defects of mitochondrial-encoded OXPHOS subunits have been found in normal and cirrhotic liver, however their contributions in hepatocellular carcinoma (HCC) are not clear. The present study aimed to examine these defects in resected HCC tissues. In total, 102 human HCC tissues were collected from patients undergoing curative resection, and immunohistochemical staining was performed to assess tissue expression of complex I subunit 6, complex III subunit 3, complex IV subunit 1 (CIV-1) and complex V subunit 6. Cox proportional hazard model analysis was performed, including all clinicopathological factors, to postoperatively estimate the overall survival rate. The results showed that the majority of HCC tissues contained various degrees of expression defects for OXPHOS subunits. Among these, the major CIV-1 defect (expression defect area of >25% of the examined area) (P<0.001) and early distant metastasis (P<0.001) were independently associated with the overall survival rate. Kaplan-Meier analysis also demonstrated that the major CIV-1 defect was significantly associated with a poor overall survival rate (log-rank, P=0.002). The findings in the present study clearly indicate that the major CIV-1 expression defect may serve as an independent negative prognostic factor in HCC patients following curative resection.
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Affiliation(s)
- Puo-Hsien LE
- Department of Gastroenterology and Hepatology, Linkou Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Taoyuan 333, Taiwan, R.O.C
| | - Shih-Chiang Huang
- Department of Pathology, Linkou Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Taoyuan 333, Taiwan, R.O.C
| | - Siew-Na Lim
- Department of Neurology, Linkou Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Taoyuan 333, Taiwan, R.O.C
| | - Chang-Hua Chou
- Department of Gastroenterology and Hepatology, Linkou Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Taoyuan 333, Taiwan, R.O.C
| | - Ta-Sen Yeh
- Department of General Surgery, Linkou Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Taoyuan 333, Taiwan, R.O.C
| | - Tse-Ching Chen
- Department of Pathology, Linkou Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Taoyuan 333, Taiwan, R.O.C
| | - Tzung-Hai Yen
- Department of Nephrology, Linkou Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Taoyuan 333, Taiwan, R.O.C
| | - Ming-Yao Su
- Department of Gastroenterology and Hepatology, Linkou Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Taoyuan 333, Taiwan, R.O.C
| | - Cheng-Tang Chiu
- Department of Gastroenterology and Hepatology, Linkou Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Taoyuan 333, Taiwan, R.O.C
| | - Chau-Ting Yeh
- Liver Research Center, Linkou Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Taoyuan 333, Taiwan, R.O.C
| | - Wey-Ran Lin
- Department of Gastroenterology and Hepatology, Linkou Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Taoyuan 333, Taiwan, R.O.C
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Du G, Sun T, Zhang Y, Lin H, Li J, Liu W, Wang Y, Zhao B, Li H, Liu Y. The mitochondrial dysfunction plays an important role in urethane-induced lung carcinogenesis. Eur J Pharmacol 2013; 715:395-404. [DOI: 10.1016/j.ejphar.2013.04.031] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2012] [Revised: 04/25/2013] [Accepted: 04/26/2013] [Indexed: 12/17/2022]
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Quarato G, Piccoli C, Scrima R, Capitanio N. Functional imaging of membrane potential at the single mitochondrion level: Possible application for diagnosis of human diseases. Mitochondrion 2011; 11:764-73. [DOI: 10.1016/j.mito.2011.06.014] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2011] [Revised: 06/12/2011] [Accepted: 06/29/2011] [Indexed: 12/23/2022]
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