Crystal structure of<scp>d</scp>-stereospecific amidohydrolase from<i>Streptomyces</i>sp. 82F2 - insight into the structural factors for substrate specificity
作者:Jiro Arima、Kana Shimone、Kazusa Miyatani、Yuka Tsunehara、Yoshitaka Isoda、Tomoya Hino、Shingo Nagano
DOI:10.1111/febs.13579
日期:2016.1
potential 1,8-diaminooctane binding site, probably with lower affinity, is present close to the active site. The enzyme kinetics and structural comparisons suggest that the location of enzyme-bound diamine can explain the inhibition of the acyl-enzyme intermediate formation, although the bound diamine is too far from the active site for aminolysis. Despite difficulty in locating the diamine binding site
来自链霉菌属(Streptomyces sp。)的未贴标签的D-立体特异性酰胺水解酶(DAH)。82F2可以催化由d-氨基酰基酯和l-氨基酸形成酰胺键(氨基分解),可用于合成具有dl-构型的短肽。我们发现DAH可以在氨解反应中使用1,8-二氨基辛烷和其他氨基化合物作为酰基受体。低浓度的1,8-二氨基辛烷会抑制酰基-DAH中间体的形成。相比之下,过量的1,8-二氨基辛烷通过DAH促进氨解,通过二胺对酶结合的d-Phe的亲核攻击产生d-Phe-1,8-二氨基辛烷。为了阐明DAH底物特异性和酰胺键形成的机理,以1.49Å的分辨率测定了结合1,8-二氨基辛烷的酶的晶体结构。DAH晶体结构与S12肽酶家族其他成员的晶体结构比较表明,DAH的底物特异性来自其活性位点结构。1,8-二氨基辛烷分子在活性位点口袋的入口处结合。电子密度图显示在活性位点附近存在另一个潜在的1,8-二氨基辛烷结合位点,可能具有较