Structural basis of the substrate recognition of hydrazidase isolated from Microbacterium sp. strain HM58-2, which catalyzes acylhydrazide compounds as its sole carbon source
作者:Tomonori Akiyama、Misaki Ishii、Atsushi Takuwa、Ken-Ichi Oinuma、Yasuyuki Sasaki、Naoki Takaya、Shunsuke Yajima
DOI:10.1016/j.bbrc.2016.11.148
日期:2017.1
strain HM58-2. The active site was revealed to consist of a Ser-cisSer-Lys catalytic triad, in which Ser179 forms a covalent bond with a carbonyl carbon of the substrate. 4-Hydroxybenzoic acid hydrazide bound to the S179A mutant, showing an oxyanion hole composed of the three backbone amide groups. Furthermore, H336 in the non-conserved region in the amidase family may define the substrate specificity, which
透明质酸酶是半个世纪以来一直未被发现的酶。然而,最近,它被纯化,并且其编码基因被克隆。微小杆菌 HM58-2菌株以酰肼为唯一碳源生长。它产生酰肼酶并将酰肼降解为乙酸盐和酰肼。细菌酰肼酶属于酰胺酶签名酶家族,并含有Ser-cisSer-Lys催化基序。肼和碳酸的缩合产生各种酰肼,其中某些酰肼是合成药物和其他有用化学物质的原料。尽管已经鉴定出天然的酰肼化合物,但是对于酰肼的代谢系统还没有完全了解。在这里,我们报告了来自Microbacterium sp。的肼基酶的晶体结构。菌株HM58-2。揭示了该活性位点由Ser-cisSer-Lys催化三联体组成,其中Ser179与底物的羰基碳形成共价键。与S179A突变体结合的4-羟基苯甲酸酰肼,显示由三个主链酰胺基团组成的氧阴离子孔。此外,酰胺酶家族非保守区中的H336可以定义底物特异性,这通过突变分析得到证实。野生型载脂酶结构揭示了与S179共价结合