Identification of new enzymes potentially involved in anaerobic naphthalene degradation by the sulfate-reducing enrichment culture N47
Identification of new enzymes potentially involved in anaerobic naphthalene degradation by the sulfate-reducing enrichment culture N47
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DOI：
10.1007/s00203-010-0667-4
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发表时间：
2011-04-01
影响因子：
2.8
通讯作者：
Meckenstock, Rainer U.
中科院分区：
文献类型：
--
作者：
Bergmann, Franz D.;Selesi, Drazenka;Meckenstock, Rainer U.
硫酸盐还原高富集培养物N47能够厌氧降解萘、2-甲基萘和2-萘甲酸。利用蛋白质基因组学研究了萘厌氧降解的初始活化反应。这导致鉴定了羧化酶蛋白的α-亚基，与2-甲基萘生长的细胞相比，其在萘生长的细胞中上调两倍。推定的萘羧化酶亚基表现出48%的相似性厌氧苯羧化酶从铁还原，苯降解文化和45%的α-亚基的苯磷酸羧化酶的芳香族香料EbN 1。推测的萘羧化酶的β亚基的基因位于基因组附近，并与萘一起表达。类似于厌氧苯羧化酶，没有基因的γ-和δ-亚基的一个假定的羧化酶蛋白位于基因组上，排除参与降解的酚类化合物。推定的萘羧化酶亚基的基因鉴定显示，除了ATP非依赖性羧化作用外，只有微弱的相似性4-羟基苯甲酸脱羧酶。几个ORF被鉴定为可能编码2-萘甲酸-CoA连接酶，其在随后的萘酰-CoA还原酶环还原之前专性活化。其中一种连接酶仅在萘和2-萘甲酸上表达，可能是负责的萘酸-CoA-连接酶。
The sulfate-reducing highly enriched culture N47 is capable to anaerobically degrade naphthalene, 2-methylnaphthalene, and 2-naphthoic acid. A proteogenomic investigation was performed to elucidate the initial activation reaction of anaerobic naphthalene degradation. This lead to the identification of an alpha-subunit of a carboxylase protein that was two-fold up-regulated in naphthalene-grown cells compared to 2-methylnaphthalene-grown cells. The putative naphthalene carboxylase subunit showed 48% similarity to the anaerobic benzene carboxylase from an iron-reducing, benzene-degrading culture and 45% to alpha-subunit of phenylphosphate carboxylase of Aromatoleum aromaticum EbN1. A gene for the beta-subunit of putative naphthalene carboxylase was located nearby on the genome and was expressed with naphthalene. Similar to anaerobic benzene carboxylase, there were no genes for gamma-and delta-subunits of a putative carboxylase protein located on the genome which excludes participation in degradation of phenolic compounds. The genes identified for putative naphthalene carboxylase subunits showed only weak similarity to 4-hydroxybenzoate decarboxylase excluding ATP-independent carboxylation. Several ORFs were identified that possibly encode a 2-naphthoate-CoA ligase, which is obligate for activation before the subsequent ring reduction by naphthoyl-CoA reductase. One of these ligases was exclusively expressed on naphthalene and 2-naphthoic acid and might be the responsible naphthoate-CoA-ligase.