John-White Marietta, Dumsday Geoff J, Johanesen Priscilla, Lyras Dena, Drinkwater Nyssa, McGowan Sheena
Biomedicine Discovery Institute, Department of Microbiology, Monash University, Clayton, Melbourne, VIC 3800, Australia.
Manufacturing, CSIRO, Clayton, Melbourne, VIC 3800, Australia.
Acta Crystallogr F Struct Biol Commun. 2017 Jul 1;73(Pt 7):386-392. doi: 10.1107/S2053230X17007737. Epub 2017 Jun 17.
β-Aminopeptidases are a unique group of enzymes that have the unusual capability to hydrolyze N-terminal β-amino acids from synthetic β-peptides. β-Peptides can form secondary structures mimicking α-peptide-like structures that are resistant to degradation by most known proteases and peptidases. These characteristics of β-peptides give them great potential as peptidomimetics. Here, the X-ray crystal structure of BcA5-BapA, a β-aminopeptidase from a Gram-negative Burkholderia sp. that was isolated from activated sludge from a wastewater-treatment plant in Australia, is reported. The crystal structure of BcA5-BapA was determined to a resolution of 2.0 Å and showed a tetrameric assembly typical of the β-aminopeptidases. Each monomer consists of an α-subunit (residues 1-238) and a β-subunit (residues 239-367). Comparison of the structure of BcA5-BapA with those of other known β-aminopeptidases shows a highly conserved structure and suggests a similar proteolytic mechanism of action.
β-氨基肽酶是一类独特的酶，具有从合成β-肽中水解N端β-氨基酸的非凡能力。β-肽可以形成模仿α-肽样结构的二级结构，这些结构对大多数已知的蛋白酶和肽酶具有抗性。β-肽的这些特性使其作为肽模拟物具有巨大潜力。在此，报道了一种来自革兰氏阴性伯克霍尔德菌属的β-氨基肽酶BcA5-BapA的X射线晶体结构，该酶是从澳大利亚一家污水处理厂的活性污泥中分离得到的。BcA5-BapA的晶体结构分辨率为2.0 Å，显示出典型的β-氨基肽酶四聚体组装。每个单体由一个α亚基（第1-238位残基）和一个β亚基（第239-367位残基）组成。将BcA5-BapA的结构与其他已知β-氨基肽酶的结构进行比较，发现其结构高度保守，并提示其蛋白水解作用机制相似。
