Istituto di Biostrutture e Bioimmagini-CNR, via Mezzocannone 16, 80134 Napoli, Italy.
Biopolymers. 2010 Aug;93(8):669-77. doi: 10.1002/bip.21420.
S-formylglutathione hydrolases (FGHs) constitute a family of ubiquitous enzymes which play a key role in formaldehyde detoxification both in prokaryotes and eukaryotes, catalyzing the hydrolysis of S-formylglutathione to formic acid and glutathione. While a large number of functional studies have been reported on these enzymes, few structural studies have so far been carried out. In this article we report on the functional and structural characterization of PhEst, a FGH isolated from the psychrophilic bacterium Pseudoalteromonas haloplanktis. According to our functional studies, this enzyme is able to efficiently hydrolyze several thioester substrates with very small acyl moieties. By contrast, the enzyme shows no activity toward substrates with bulky acyl groups. These data are in line with structural studies which highlight for this enzyme a very narrow acyl-binding pocket in a typical alpha/beta-hydrolase fold. PhEst represents the first cold-adapted FGH structurally characterized to date; comparison with its mesophilic counterparts of known three-dimensional structure allowed to obtain useful insights into molecular determinants responsible for the ability of this psychrophilic enzyme to work at low temperature.
S-甲酰基谷胱甘肽水解酶（FGHs）构成了一个广泛存在的酶家族，在原核生物和真核生物中都在甲醛解毒中发挥着关键作用，催化 S-甲酰基谷胱甘肽水解生成甲酸和谷胱甘肽。虽然已经有大量关于这些酶的功能研究报告，但到目前为止，很少有结构研究。在本文中，我们报告了从嗜冷菌假交替单胞菌中分离得到的 FGH PhEst 的功能和结构特征。根据我们的功能研究，该酶能够有效地水解具有非常小酰基部分的几种硫酯底物。相比之下，该酶对具有大酰基基团的底物没有活性。这些数据与结构研究一致，该研究强调了该酶在典型的α/β-水解酶折叠中具有非常狭窄的酰基结合口袋。PhEst 是迄今为止结构上表征的第一个适应寒冷的 FGH；与已知三维结构的其嗜温对应物进行比较，为理解这种嗜冷酶在低温下工作的分子决定因素提供了有用的见解。
