Branched-chain fatty acid biosynthesis in a branched-chain amino acid aminotransferase mutant of Staphylococcus carnosus
Branched-chain fatty acid biosynthesis in a branched-chain amino acid aminotransferase mutant of Staphylococcus carnosus
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DOI：
10.1016/j.femsle.2004.11.041
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发表时间：
2005-02-01
影响因子：
2.1
通讯作者：
Beck, HC
中科院分区：
文献类型：
--
作者：
Beck, HC
分析了一株支链氨基酸氨基转移酶（IIvE）活性缺陷的肉葡萄球菌突变株的脂肪酸生物合成。该突变体不能产生用于支链脂肪酸生物合成的合适的支链α-酮酸前体氨基酸缬氨酸、异亮氨酸和亮氨酸，并且需要短支链酸2-甲基丁酸或2-甲基丙酸用于在限定培养基中生长。异亮氨酸相关代谢物α-酮基-β-甲基戊酸和2-甲基丁醛也可作为生长因子。在丰富培养基中生长和在补充有2-甲基丙酸的限定培养基中生长导致细胞膜中脂肪酸组成的广泛改变。在丰富的培养基中，与野生型菌株相比，观察到从51.7%至17.1%的反异-C-15：0和从3.6%至33.9%的异-C-14：0脂肪酸的变化。尽管该突变株在livE活性方面存在缺陷，但当在丰富培养基中培养时，该突变株仍能够产生短链羧酸、3-甲基丁酸和2-甲基丙酸。采用氘代葡萄糖的补充实验诱导了用于2-甲基丙酸生产的缬氨酸生物合成途径，揭示了IlvE蛋白在S.肉质的(C)2004年，欧洲微生物学会联合会。Elsevier B. V.出版，保留所有权利。
Fatty acid biosynthesis by a mutant strain of Staphlylococcus carnosus deficient in branched-chain amino acid aminotransferase (IIvE) activity was analysed. This mutant was unable to produce the appropriate branched-chain alpha-ketoacid precursors for branched-chain fatty acid biosynthesis front the amino acids valine, isoleucine, and leucine, and required the short branched chain acids 2-methylbutanoic acid or 2-methylpropanoic acid for growth in a defined medium. The isoleucine related metabolites, alpha-keto-beta-methylvaleric acid and 2-methylbutanal also served as growth factors. Growth in rich medium and growth in defined medium supplemented with 2-methylpropanoic acid lead to extensive alteration of the fatty acid composition in the cell membrane. In rich medium, a change from 51.7% to 17.1% anteiso-C-15:0, and from 3.6% to 33.9% iso-C-14:0 fatty acids as compared to the wild-type strain was observed. Despite the deficiency in lIvE activity, the mutant strain was still able to produce the short chain carboxylic acids, 3-methylbutanoic acid and 2-methylpropanoic acid when cultivated in rich medium. Supplementation experiments employing deuterated glucose induced the valine biosynthetic pathway for 2-methylpropanoic acid production, revealing that the IlvE protein plays an important, but not essential role in the biosynthesis of branched-chain fatty acids and secondary metabolites in S. carnosus. (C) 2004 Federation of European Microbiological Societies. Published by Elsevier B.V. All rights reserved.