2Z8K

Crystal Structure of Escherichia coli gamma-Glutamyltranspeptidase in Complex with Acivicin

2Z8K の概要

• エントリーDOI: 10.2210/pdb2z8k/pdb
• 関連するPDBエントリー: 2Z8I 2Z8J
• 分子名称: Gamma-glutamyltranspeptidase, (2S)-AMINO[(5S)-3-CHLORO-4,5-DIHYDROISOXAZOL-5-YL]ACETIC ACID, ... (4 entities in total)
• 機能のキーワード: acivicin formed a covalent bond with thr391, acyltransferase, glutathione biosynthesis, transferase, zymogen
• 由来する生物種: Escherichia coli; 詳細
• 細胞内の位置: Periplasm: P18956 P18956
• タンパク質・核酸の鎖数: 4
• 化学式量合計: 119036.56

構造登録者

Wada, K.,Irie, M.,Fukuyama, K. (登録日: 2007-09-05, 公開日: 2008-06-24, 最終更新日: 2024-11-20)

主引用文献

Wada, K.,Hiratake, J.,Irie, M.,Okada, T.,Yamada, C.,Kumagai, H.,Suzuki, H.,Fukuyama, K.
Crystal structures of Escherichia coli gamma-glutamyltranspeptidase in complex with azaserine and acivicin: novel mechanistic implication for inhibition by glutamine antagonists
J.Mol.Biol., 380:361-372, 2008

PubMed Abstract: gamma-Glutamyltranspeptidase (GGT) catalyzes the cleavage of such gamma-glutamyl compounds as glutathione, and the transfer of their gamma-glutamyl group to water or to other amino acids and peptides. GGT is involved in a number of biological phenomena such as drug resistance and metastasis of cancer cells by detoxification of xenobiotics. Azaserine and acivicin are classical and irreversible inhibitors of GGT, but their binding sites and the inhibition mechanisms remain to be defined. We have determined the crystal structures of GGT from Escherichia coli in complex with azaserine and acivicin at 1.65 A resolution. Both inhibitors are bound to GGT at its substrate-binding pocket in a manner similar to that observed previously with the gamma-glutamyl-enzyme intermediate. They form a covalent bond with the O(gamma) atom of Thr391, the catalytic residue of GGT. Their alpha-carboxy and alpha-amino groups are recognized by extensive hydrogen bonding and charge interactions with the residues that are conserved among GGT orthologs. The two amido nitrogen atoms of Gly483 and Gly484, which form the oxyanion hole, interact with the inhibitors directly or via a water molecule. Notably, in the azaserine complex the carbon atom that forms a covalent bond with Thr391 is sp(3)-hybridized, suggesting that the carbonyl of azaserine is attacked by Thr391 to form a tetrahedral intermediate, which is stabilized by the oxyanion hole. Furthermore, when acivicin is bound to GGT, a migration of the single and double bonds occurs in its dihydroisoxazole ring. The structural characteristics presented here imply that the unprecedented binding modes of azaserine and acivicin are conserved in all GGTs from bacteria to mammals and give a new insight into the inhibition mechanism of glutamine amidotransferases by these glutamine antagonists.

PubMed: 18555071
DOI: 10.1016/j.jmb.2008.05.007

実験手法

X-RAY DIFFRACTION (1.65 Å)