Role of water and protein dynamics in proton pumping by respiratory complex I

Abstract Membrane bound respiratory complex I is the key enzyme in the respiratory chains of bacteria and mitochondria, and couples the reduction of quinone to the pumping of protons across the membrane. Recently solved crystal or electron microscopy structures of bacterial and mitochondrial complex...

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Autores principales:	Outi Haapanen, Vivek Sharma
Formato:	article
Lenguaje:	EN
Publicado:	Nature Portfolio 2017
Materias:	Medicine R Science Q
Acceso en línea:	https://doaj.org/article/5d140705adc9472d959b9f3bbdfeba67
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spelling	oai:doaj.org-article:5d140705adc9472d959b9f3bbdfeba672021-12-02T16:08:23ZRole of water and protein dynamics in proton pumping by respiratory complex I10.1038/s41598-017-07930-12045-2322https://doaj.org/article/5d140705adc9472d959b9f3bbdfeba672017-08-01T00:00:00Zhttps://doi.org/10.1038/s41598-017-07930-1https://doaj.org/toc/2045-2322Abstract Membrane bound respiratory complex I is the key enzyme in the respiratory chains of bacteria and mitochondria, and couples the reduction of quinone to the pumping of protons across the membrane. Recently solved crystal or electron microscopy structures of bacterial and mitochondrial complexes have provided significant insights into the electron and proton transfer pathways. However, due to large spatial separation between the electron and proton transfer routes, the molecular mechanism of coupling remains unclear. Here, based on atomistic molecular dynamics simulations performed on the entire structure of complex I from Thermus thermophilus, we studied the hydration of the quinone-binding site and the membrane-bound subunits. The data from simulations show rapid diffusion of water molecules in the protein interior, and formation of hydrated regions in the three antiporter-type subunits. An unexpected water-protein based connectivity between the middle of the Q-tunnel and the fourth proton channel is also observed. The protonation-state dependent dynamics of key acidic residues in the Nqo8 subunit suggest that the latter may be linked to redox-coupled proton pumping in complex I. We propose that in complex I the proton and electron transfer paths are not entirely separate, instead the nature of coupling may in part be ‘direct’.Outi HaapanenVivek SharmaNature PortfolioarticleMedicineRScienceQENScientific Reports, Vol 7, Iss 1, Pp 1-12 (2017)
institution	DOAJ
collection	DOAJ
language	EN
topic	Medicine R Science Q
spellingShingle	Medicine R Science Q Outi Haapanen Vivek Sharma Role of water and protein dynamics in proton pumping by respiratory complex I
description	Abstract Membrane bound respiratory complex I is the key enzyme in the respiratory chains of bacteria and mitochondria, and couples the reduction of quinone to the pumping of protons across the membrane. Recently solved crystal or electron microscopy structures of bacterial and mitochondrial complexes have provided significant insights into the electron and proton transfer pathways. However, due to large spatial separation between the electron and proton transfer routes, the molecular mechanism of coupling remains unclear. Here, based on atomistic molecular dynamics simulations performed on the entire structure of complex I from Thermus thermophilus, we studied the hydration of the quinone-binding site and the membrane-bound subunits. The data from simulations show rapid diffusion of water molecules in the protein interior, and formation of hydrated regions in the three antiporter-type subunits. An unexpected water-protein based connectivity between the middle of the Q-tunnel and the fourth proton channel is also observed. The protonation-state dependent dynamics of key acidic residues in the Nqo8 subunit suggest that the latter may be linked to redox-coupled proton pumping in complex I. We propose that in complex I the proton and electron transfer paths are not entirely separate, instead the nature of coupling may in part be ‘direct’.
format	article
author	Outi Haapanen Vivek Sharma
author_facet	Outi Haapanen Vivek Sharma
author_sort	Outi Haapanen
title	Role of water and protein dynamics in proton pumping by respiratory complex I
title_short	Role of water and protein dynamics in proton pumping by respiratory complex I
title_full	Role of water and protein dynamics in proton pumping by respiratory complex I
title_fullStr	Role of water and protein dynamics in proton pumping by respiratory complex I
title_full_unstemmed	Role of water and protein dynamics in proton pumping by respiratory complex I
title_sort	role of water and protein dynamics in proton pumping by respiratory complex i
publisher	Nature Portfolio
publishDate	2017
url	https://doaj.org/article/5d140705adc9472d959b9f3bbdfeba67
work_keys_str_mv	AT outihaapanen roleofwaterandproteindynamicsinprotonpumpingbyrespiratorycomplexi AT viveksharma roleofwaterandproteindynamicsinprotonpumpingbyrespiratorycomplexi
_version_	1718384530724749312

Role of water and protein dynamics in proton pumping by respiratory complex I

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