title: Potential involvement of N-terminal acetylation in the quantitative regulation of the ε subunit of chloroplast ATP synthase under drought stress.
abstract: In plants, modulation of photosynthetic energy conversion in varying environments is often accompanied by adjustment of the abundance of photosynthetic components. In wild watermelon (Citrullus lanatus L.), proteome analysis revealed that the ε subunit of chloroplast ATP synthase occurs as two distinct isoforms with largely-different isoelectric points, although encoded by a single gene. Mass spectrometry (MS) analysis of the ε isoforms indicated that the structural difference between the ε isoforms lies in the presence or absence of an acetyl group at the N-terminus. The protein level of the non-acetylated ε isoform preferentially decreased in drought, whereas the abundance of the acetylated ε isoform was unchanged. Moreover, metalloprotease activity that decomposed the ε subunit was detected in a leaf extract from drought-stressed plants. Furthermore, in vitro assay suggested that the non-acetylated ε subunit was more susceptible to degradation by metalloaminopeptidase. We propose a model in which quantitative regulation of the ε subunit involves N-terminal acetylation and stress-induced proteases.
authors: Graduate School of Biological Sciences, Nara Institute of Science and Technology (NAIST), Ikoma, Nara, Japan.
authors: Saki
authors: S
authors: Hoshiyasu
authors: Kaori
authors: K
authors: Kohzuma
authors: Kazuo
authors: K
authors: Yoshida
authors: Masayuki
authors: M
authors: Fujiwara
authors: Yoichiro
authors: Y
authors: Fukao
authors: Akiho
authors: A
authors: Yokota
authors: Kinya
authors: K
authors: Akashi
mesh_terms: D000107:Acetylation; D000255:Adenosine Triphosphate / Q000096:biosynthesis; D000595:Amino Acid Sequence; D000626:Aminopeptidases / Q000378:metabolism; D025222:Chloroplast Proton-Translocating ATPases / Q000737:chemistry* / Q000378:metabolism*; D029773:Citrullus / Q000201:enzymology* / Q000378:metabolism / Q000502:physiology; D055864:Droughts; D006868:Hydrolysis; D007527:Isoenzymes / Q000737:chemistry / Q000378:metabolism; D008969:Molecular Sequence Data; D021122:Protein Subunits / Q000737:chemistry* / Q000378:metabolism*; D013312:Stress, Physiological
chemical_list: D007527:Isoenzymes; D021122:Protein Subunits; D000255:Adenosine Triphosphate; D000626:Aminopeptidases; D025222:Chloroplast Proton-Translocating ATPases