Salicylate degradation by a cold-adapted Pseudomonas sp.
Salicylate degradation by a cold-adapted Pseudomonas sp.
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DOI：
10.1007/s13213-017-1273-3
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发表时间：
2017-06-01
影响因子：
3
通讯作者：
Kim, Eungbin
中科院分区：
文献类型：
--
作者：
Ahn, Eunsol;Choi, Ki Young;Kim, Eungbin
假单胞菌属菌株MC 1被表征为能够在5- 30 A ℃的宽温度范围内生长的冷适应的萘降解细菌。MC 1含有一个分解代谢质粒，命名为pYIC 1，它几乎与来自嗜温细菌恶臭假单胞菌G7的原型NAH 7质粒相同。在pYIC 1上，萘降解的分解代谢基因聚集在两个操纵子中：nahAa-Ab-Ac-Ad-B-F-C-Q-E-D编码萘转化为水杨酸盐，nahG-T-H-I-N-L-O-M-K-J编码水杨酸盐通过间位裂解途径转化为丙酮酸盐和乙酰CoA。NahH是MC 1水杨酸代谢中真正的二醇外双加氧酶，是热不稳定的，是一种冷适应酶。在不同宿主中表达的NahH酶活性的热曲线表明存在保护G7中不耐热NahH酶（与MC 1对应物100%aa同一性）的因素或机制。总体而言，在目前的工作中报告的结果表明，热不稳定NahH可能是一个产品的冷适应过程中的MC 1，从而有助于生存和生长能力的MC 1水杨酸盐和萘在寒冷的环境中。
Pseudomonas sp. strain MC1 was characterized as a cold-adapted, naphthalene-degrading bacterium that is able to grow in a broad temperature range of 5-30A degrees C. MC1 harbors a catabolic plasmid, designated pYIC1, which is almost identical to the archetypal NAH7 plasmid from the mesophilic bacterium Pseudomonas putida G7. On pYIC1, the catabolic genes for naphthalene degradation are clustered in two operons: nahAa-Ab-Ac-Ad-B-F-C-Q-E-D encoding the conversion of naphthalene to salicylate, and nahG-T-H-I-N-L-O-M-K-J encoding the conversion of salicylate through meta-cleavage pathway to pyruvate and acetyl CoA. NahH, the bona fide extradiol dioxygenase in MC1 salicylate metabolism, is thermolabile and is a cold-adapted enzyme. The thermal profiles of the NahH enzyme activities expressed in different hosts indicate the presence of a factor(s) or mechanism(s) to protect the thermolabile NahH enzyme (100% aa identity with MC1 counterpart) in G7. Overall, the results reported in the present work suggest that the thermolabile NahH might be a product of the cold-adaptation process of MC1 and thus contribute to the survival and growth ability of MC1 on salicylate and naphthalene in cold environments.