人ACCS的半胱氨酸S-共轭亚砜β-裂合酶活性。
Cysteine S-conjugate sulfoxide β-lyase activity for human ACCS.
作者信息
Gao Jinmin, Xu Yueqi, Yeh Christopher, Zou Yike, Hai Yang
机构信息
Department of Chemistry and Biochemistry, University of California, Santa Barbara, CA, USA.
Department of Molecular, Cellular, and Developmental Biology, University of California, Santa Barbara, CA, USA.
出版信息
FEBS J. 2025 May;292(9):2272-2286. doi: 10.1111/febs.17419. Epub 2025 Jan 28.
1-Aminocyclopropane-1-carboxylate synthase (ACCS) catalyzes the conversion of S-adenosyl-methionine to 1-aminocyclopropane-1-carboxylate (ACC), a rate-limiting step in ethylene biosynthesis. A gene encoding a putative ACCS protein was identified in the human genome two decades ago. It has been shown to not exhibit any canonical ACC synthase activity and its true function remains obscure. In this study, through a biochemical profiling approach, we demonstrate that human ACCS possesses cysteine conjugate sulfoxide β-lyase activity. This function is unexpected but reasonable, as it somewhat parallels the activity of ACCS proteins found in non-seed plants. Structure-function relationship study of human ACCS, guided by an AlphaFold2 model, allowed us to identify key active site residues that are important for its β-lyase activity. Our biochemical study of human ACCS also provided insights into the function of other mammalian ACCS homologs.
1-氨基环丙烷-1-羧酸合酶（ACCS）催化S-腺苷甲硫氨酸转化为1-氨基环丙烷-1-羧酸（ACC），这是乙烯生物合成中的限速步骤。二十年前在人类基因组中鉴定出一个编码假定ACCS蛋白的基因。已证明它不表现出任何典型的ACC合酶活性，其真正功能仍然不清楚。在本研究中，通过生化分析方法，我们证明人类ACCS具有半胱氨酸共轭亚砜β-裂合酶活性。这个功能出乎意料但合理，因为它在某种程度上与非种子植物中发现的ACCS蛋白的活性相似。在AlphaFold2模型的指导下，对人类ACCS进行结构-功能关系研究，使我们能够鉴定出对其β-裂合酶活性重要的关键活性位点残基。我们对人类ACCS的生化研究也为其他哺乳动物ACCS同源物的功能提供了见解。
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