气候变化领域集成服务门户(CCPortal): Citramalate synthase yields a biosynthetic pathway for isoleucine and straight- And branched-chain ester formation in ripening apple fruit

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DOI	10.1073/pnas.2009988118
	Citramalate synthase yields a biosynthetic pathway for isoleucine and straight- And branched-chain ester formation in ripening apple fruit
	Sugimoto N.; Engelgau P.; Daniel Jones A.; Song J.; Beaudry R.
发表日期	2021
ISSN	00278424
卷号	118 期号:3
英文摘要	A plant pathway that initiates with the formation of citramalate from pyruvate and acetyl-CoA by citramalate synthase (CMS) is shown to contribute to the synthesis of α-ketoacids and important odor-active esters in apple (Malus × domestica) fruit. Microarray screening led to the discovery of a gene with high amino acid similarity to 2-isopropylmalate synthase (IPMS). However, functional analysis of recombinant protein revealed its substrate preference differed substantially from IPMS and was more typical of CMS. MdCMS also lacked the regulatory region present in MdIPMS and was not sensitive to feedback inhibition. 13C-acetate feeding of apple tissue labeled citramalate and α-ketoacids in a manner consistent with the presence of the citramalate pathway, labeling both straight- and branched-chain esters. Analysis of genomic DNA (gDNA) revealed the presence of two nearly identical alleles in “Jonagold” fruit (MdCMS_1 and MdCMS_2), differing by two nonsynonymous single-nucleotide polymorphisms (SNPs). The mature proteins differed only at amino acid 387, possessing either glutamine387 (MdCMS_1) or glutamate387 (MdCMS_2). Glutamate387 was associated with near complete loss of activity. MdCMS expression was fruit-specific, increasing severalfold during ripening. The translated protein product was detected in ripe fruit. Transient expression of MdCMS_1 in Nicotiana benthamiana induced the accumulation of high levels of citramalate, whereas MdCMS_2 did not. Domesticated apple lines with MdCMS isozymes containing only glutamate387 produced a very low proportion of 2-methylbutanol- and 2-methylbutanoate (2MB) and 1-propanol and propanoate (PROP) esters. The citramalate pathway, previously only described in microorganisms, is shown to function in ripening apple and contribute to isoleucine and 2MB and PROP ester biosynthesis without feedback regulation. © 2021 National Academy of Sciences. All rights reserved.
英文关键词	Citramalate; Esters; Fruit; Isoleucine; Ripening
语种	英语
scopus关键词	citramalate synthase; glutamine; isoleucine; synthetase; unclassified drug; amino acid synthesis; apple; Article; biosynthesis; controlled study; fruit ripening; gene expression; microorganism; nonhuman; priority journal; single nucleotide polymorphism
来源期刊	Proceedings of the National Academy of Sciences of the United States of America
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/180964
作者单位	Department of Horticulture, Michigan State University, East Lansing, MI 48824, United States; Mass Spectrometry and Metabolomics Core, Research Technology Support Facility, Michigan State University, East Lansing, MI 48824, United States; Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824, United States; Department of Chemistry, Michigan State University, East Lansing, MI 48824, United States; Kentville Research and Development Center, Agriculture and Agri-Food Canada, Kentville, NS B4N 1J5, Canada
推荐引用方式 GB/T 7714	Sugimoto N.,Engelgau P.,Daniel Jones A.,et al. Citramalate synthase yields a biosynthetic pathway for isoleucine and straight- And branched-chain ester formation in ripening apple fruit[J],2021,118(3).
APA	Sugimoto N.,Engelgau P.,Daniel Jones A.,Song J.,&Beaudry R..(2021).Citramalate synthase yields a biosynthetic pathway for isoleucine and straight- And branched-chain ester formation in ripening apple fruit.Proceedings of the National Academy of Sciences of the United States of America,118(3).
MLA	Sugimoto N.,et al."Citramalate synthase yields a biosynthetic pathway for isoleucine and straight- And branched-chain ester formation in ripening apple fruit".Proceedings of the National Academy of Sciences of the United States of America 118.3(2021).