title: Caenorhabditis elegans MAI-1 protein, which is similar to mitochondrial ATPase inhibitor (IF1), can inhibit yeast F0F1-ATPase but cannot be transported to yeast mitochondria.
abstract: In Caenorhabditis elegans, two proteins that are similar to mitochondrial ATPase inhibitor protein (IF(1)) have been found and named MAI-1 and MAI-2. In this study, we overexpressed and purified both the proteins and examined their properties. Circular dichroism spectra indicated that both the MAI-1 and MAI-2 predominantly consisted of beta- and random structure, and in contrast to mammalian IF(1), alpha-helixes were barely detected. Both MAI-1 and MAI-2 could inhibit yeast F(0)F(1)-ATPase, but the inhibition by MAI-1 was pH-independent. MAI-2-GFP fusion protein was transported to yeast mitochondria, but MAI-1-GFP was not. These results indicate that the MAI-2 is (C. elegans) IF(1). MAI-1 seems to be a cytosolic protein and may regulate cytosolic ATPase(s).
authors.affiliation: Department of Food and Nutrition, Faculty of Human Life Science, Osaka City University, 3-3-138 Sugimoto, Sumiyoshi, Osaka, 558-8585, Japan. ichikawa@life.osaka-cu.ac.jp
authors.forename: Naoki
authors.initials: N
authors.lastname: Ichikawa
authors.forename: Chiyoko
authors.initials: C
authors.lastname: Ando
authors.forename: Mina
authors.initials: M
authors.lastname: Fumino
mesh_terms: D000595:Amino Acid Sequence; D029742:Caenorhabditis elegans Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D002942:Circular Dichroism; D003600:Cytosol / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D008928:Mitochondria / Q000378:metabolism; D008969:Molecular Sequence Data; D017433:Protein Structure, Secondary; D021381:Protein Transport; D011506:Proteins / Q000235:genetics; D006180:Proton-Translocating ATPases / Q000037:antagonists & inhibitors*; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000235:genetics; D012441:Saccharomyces cerevisiae / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000037:antagonists & inhibitors* / Q000378:metabolism; D000097795:ATPase Inhibitory Protein
chemical_list: D029742:Caenorhabditis elegans Proteins; D011506:Proteins; D006180:Proton-Translocating ATPases; D011993:Recombinant Fusion Proteins; D029701:Saccharomyces cerevisiae Proteins; D000097795:ATPase Inhibitory Protein; C519157:MAI-1 protein, C elegans; C519158:MAI-2 protein, C elegans