Li Jine, Wang Min, Ding Yong, Tang Yue, Zhang Zhiguo, Chen Yihua
State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China.
University of Chinese Academy of Sciences, Beijing, 110039, China.
Sci Rep. 2016 Feb 15;6:21180. doi: 10.1038/srep21180.
C-4 hydroxyethyl branched octoses have been observed in polysaccharides of several genera of gram negative bacteria and in various antibiotics produced by gram positive bacteria. The C-4 hydroxyethyl branch was proposed to be converted from C-4 acetyl branch by an uncharacterized ketoreduction step. Paulomycins (PAUs) are glycosylated antibiotics with potent inhibitory activity against gram positive bacteria and are structurally defined by its unique C-4' hydroxyethyl branched paulomycose moiety. A novel aldo-keto-reductase, Pau7 was characterized as the enzyme catalyzing the stereospecific ketoreduction of 7'-keto of PAU E (1) to give the C-4' hydroxyethyl branched paulomycose moiety of PAU F (2). An acyltransferase Pau6 further decorates the C-4' hydroxyethyl branch of paulomycose moiety of 2 by attaching various fatty acyl chains to 7'-OH to generate diverse PAUs. In addition, another acyltransferase Pau24 was proposed to be responsible for the 13-O-acetylation of PAUs.
在几种革兰氏阴性菌的多糖以及革兰氏阳性菌产生的各种抗生素中，已观察到C-4羟乙基支链辛糖。有人提出，C-4羟乙基支链是通过一个未明确的酮还原步骤从C-4乙酰基支链转化而来的。保洛霉素（PAUs）是一类糖基化抗生素，对革兰氏阳性菌具有强大的抑制活性，其结构特点是具有独特的C-4'羟乙基支链的保洛糖部分。一种新型醛酮还原酶Pau7被鉴定为催化将保洛霉素E（1）的7'-酮立体选择性还原为保洛霉素F（2）的C-4'羟乙基支链保洛糖部分的酶。一种酰基转移酶Pau6通过将各种脂肪酰链连接到7'-OH上，进一步修饰2的保洛糖部分的C-4'羟乙基支链，从而产生多种保洛霉素。此外，另一种酰基转移酶Pau24被认为负责保洛霉素的13-O-乙酰化。
