The Structure of L-Hydantoinase from Arthobacter aurescens Leads to an Understanding of Dihydropyrimidinase Substrate and Enantio Specificity
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- 作者：Jan Abendroth ; Karsten Niefind ; Oliver May ; Martin Siemann ; Christoph Syldatk ; and Dietmar Schomburg
- 刊名：Biochemistry
- 出版年：2002
- 出版时间：July 9, 2002
- 年：2002
- 卷：41
- 期：27
- 页码：8589 - 8597
- 全文大小：587K
- 年卷期：v.41,no.27(July 9, 2002)
- ISSN：1520-4995
文摘
L-Hydantoinase from Arthrobacter aurescens (L-Hyd) is a member of the dihydropyrimidinaseswhich in turn belong to the cyclic amidases. Dihydropyrimidinases catalyze the reversible hydrolytic ringopening of dihydropyrimidines as the second step in the catabolism of pyrimidines. In biotechnology,their hydroloytic activity on five-membered cyclic diamides (hydantoins) is used in the enantio-specificproduction of amino acids from racemic hydantoins. L-Hyd differs from most of the other dihydropyrimidinases by an L-enantio specificity and by lacking activity on possible natural substrates such asdihydropyrimidines. In this paper, we describe the three-dimensional structure of L-Hyd which was solvedby molecular replacement using a homology model and subsequently refined to 2.6 Å resolution. Eachsubunit of the tetrameric L-Hyd consists of an elliptically distorted (
/
)8-barrel domain, which hosts theactive site, and a -sheet domain. In the active site, a binuclear zinc center activates a water molecule fornucleophilic attack on the substrates' amide bond. L-Hyd shows a strong homology both in fold and inmetal coordination in the active site to another dihydropyrimidinase from Thermus sp. (D-hydantoinase)and to a slightly lesser degree to ureases, dihydroorotase and phosphotriesterase. Using the homology toureases, a model for the transition state was modeled in the active site of L-Hyd and D-hydantoinase. Thismodel could provide an explanation for the different substrate and enantio selectivities of bothdihydropyrimidinases.
/)8-barrel domain, which hosts theactive site, and a -sheet domain. In the active site, a binuclear zinc center activates a water molecule fornucleophilic attack on the substrates' amide bond. L-Hyd shows a strong homology both in fold and inmetal coordination in the active site to another dihydropyrimidinase from Thermus sp. (D-hydantoinase)and to a slightly lesser degree to ureases, dihydroorotase and phosphotriesterase. Using the homology toureases, a model for the transition state was modeled in the active site of L-Hyd and D-hydantoinase. Thismodel could provide an explanation for the different substrate and enantio selectivities of bothdihydropyrimidinases.