title: Essential regions in the membrane domain of bacterial complex I (NDH-1): the machinery for proton translocation.
abstract: The proton-translocating NADH-quinone oxidoreductase (complex I/NDH-1) is the first and largest enzyme of the respiratory chain which has a central role in cellular energy production and is implicated in many human neurodegenerative diseases and aging. It is believed that the peripheral domain of complex I/NDH-1 transfers the electron from NADH to Quinone (Q) and the redox energy couples the proton translocation in the membrane domain. To investigate the mechanism of the proton translocation, in a series of works we have systematically studied all membrane subunits in the Escherichia coli NDH-1 by site-directed mutagenesis. In this mini-review, we have summarized our strategy and results of the mutagenesis by depicting residues essential for proton translocation, along with those for subunit connection. It is suggested that clues to understanding the driving forces of proton translocation lie in the similarities and differences of the membrane subunits, highlighting the communication of essential charged residues among the subunits. A possible proton translocation mechanism with all membrane subunits operating in unison is described.
authors: Department of Molecular and Experimental Medicine, MEM-256, The Scripps Research Institute, La Jolla, CA, 92037, USA, m.sato@nippon-soda.co.jp.
authors: Motoaki
authors: M
authors: Sato
authors: Jesus
authors: J
authors: Torres-Bacete
authors: Prem Kumar
authors: PK
authors: Sinha
authors: Akemi
authors: A
authors: Matsuno-Yagi
authors: Takao
authors: T
authors: Yagi
mesh_terms: D016227:Benzoquinones / Q000737:chemistry / Q000378:metabolism; D002462:Cell Membrane / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D042967:Electron Transport Complex I / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D004926:Escherichia coli / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D006801:Humans; D017136:Ion Transport / Q000502:physiology; D008565:Membrane Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D016297:Mutagenesis, Site-Directed; D009243:NAD / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D017434:Protein Structure, Tertiary; D021122:Protein Subunits / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D011522:Protons
chemical_list: D016227:Benzoquinones; D029968:Escherichia coli Proteins; D008565:Membrane Proteins; C540656:NuoH protein, E coli; D021122:Protein Subunits; D011522:Protons; D009243:NAD; C004532:quinone; D042967:Electron Transport Complex I