title: A conserved α helix of Bcs1, a mitochondrial AAA chaperone, is required for the Respiratory Complex III maturation.
abstract: Bcs1 is a transmembrane chaperone in the mitochondrial inner membrane, and is required for the mitochondrial Respiratory Chain Complex III assembly. It has been shown that the highly-conserved C-terminal region of Bcs1 including the AAA ATPase domain in the matrix side is essential for the chaperone function. Here we describe the importance of the N-terminal short segment located in the intermembrane space in the Bcs1 function. Among the N-terminal 44 amino acid residues of yeast Bcs1, the first 37 residues are dispensable whereas a hydrophobic amino acid in the residue 38 is essential for integration of Rieske Iron-sulfur Protein into the premature Complex III from the mitochondrial matrix. Substitution of the residue 38 by a hydrophilic amino acid residue affects conformation of Bcs1 and interactions with other proteins. The evolutionarily-conserved short α helix of Bcs1 in the intermembrane space is an essential element for the chaperone function.
authors.affiliation: Department of Molecular Cell Biology, Institute of Molecular Embryology and Genetics, Kumamoto University, Kumamoto 860-0811, Japan.
authors.forename: Rie
authors.initials: R
authors.lastname: Sawamura
authors.affiliation: Department of Molecular Cell Biology, Institute of Molecular Embryology and Genetics, Kumamoto University, Kumamoto 860-0811, Japan. Electronic address: ogura@gpo.kumamoto-u.ac.jp.
authors.forename: Teru
authors.initials: T
authors.lastname: Ogura
authors.affiliation: Department of Molecular Cell Biology, Institute of Molecular Embryology and Genetics, Kumamoto University, Kumamoto 860-0811, Japan. Electronic address: esaki@kumamoto-u.ac.jp.
authors.forename: Masatoshi
authors.initials: M
authors.lastname: Esaki
mesh_terms: D000074183:ATPases Associated with Diverse Cellular Activities; D000595:Amino Acid Sequence; D019943:Amino Acid Substitution; D003432:Cross-Linking Reagents / Q000494:pharmacology; D004072:Digitonin / Q000494:pharmacology; D014450:Electron Transport Complex III / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D007930:Leucine / Q000235:genetics; D008565:Membrane Proteins / Q000737:chemistry* / Q000378:metabolism*; D008928:Mitochondria / Q000187:drug effects / Q000378:metabolism*; D051336:Mitochondrial Membranes / Q000187:drug effects / Q000378:metabolism; D024101:Mitochondrial Proteins / Q000737:chemistry* / Q000378:metabolism*; D018832:Molecular Chaperones / Q000737:chemistry* / Q000378:metabolism*; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics; D028861:Nuclear Pore Complex Proteins / Q000737:chemistry / Q000378:metabolism; D017433:Protein Structure, Secondary; D012441:Saccharomyces cerevisiae / Q000187:drug effects / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry* / Q000378:metabolism*
chemical_list: C472685:BCS1 protein, S cerevisiae; D003432:Cross-Linking Reagents; D008565:Membrane Proteins; D024101:Mitochondrial Proteins; D018832:Molecular Chaperones; C109212:NUP42 protein, S cerevisiae; D028861:Nuclear Pore Complex Proteins; D029701:Saccharomyces cerevisiae Proteins; D000074183:ATPases Associated with Diverse Cellular Activities; D014450:Electron Transport Complex III; D007930:Leucine; D004072:Digitonin
keywords: 3,3′-dithiobis(sulfosuccinimidylpropionate); AAA; ATPases associated with diverse cellular activities; BN-PAGE; Bcs1; DTSSP; Respiratory Complex III; blue-native polyacrylamide gel electrophoresis