1BPN

DIFFERENTIATION AND IDENTIFICATION OF THE TWO CATALYTIC METAL BINDING SITES IN BOVINE LENS LEUCINE AMINOPEPTIDASE BY X-RAY CRYSTALLOGRAPHY

1BPN の概要

• エントリーDOI: 10.2210/pdb1bpn/pdb
• 分子名称: LEUCINE AMINOPEPTIDASE, ZINC ION (2 entities in total)
• 機能のキーワード: hydrolase(alpha-aminoacylpeptide)
• 由来する生物種: Bos taurus (bovine)
• 細胞内の位置: Cytoplasm: P00727
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 53072.92

構造登録者

Kim, H.,Lipscomb, W.N. (登録日: 1993-03-02, 公開日: 1993-07-15, 最終更新日: 2024-02-07)

主引用文献

Kim, H.,Lipscomb, W.N.
Differentiation and identification of the two catalytic metal binding sites in bovine lens leucine aminopeptidase by x-ray crystallography.
Proc.Natl.Acad.Sci.USA, 90:5006-5010, 1993

PubMed Abstract: The tightly binding and readily exchanging metal binding sites in the active site of bovine lens leucine aminopeptidase (blLAP; EC 3.4.11.1) have been differentiated and identified by x-ray crystallography. In native blLAP,Zn2+ occupies both binding sites. In solution, site 1 readily exchanges Zn2+ for other divalent cations, including Mg2+. The Zn2+ in site 2 is unavailable for metal exchange under conditions which allow exchange at site 1. The Zn2+/Mg2+ metal hybrid of blLAP (Mg-blLAP) was prepared in solution and crystallized. X-ray diffraction data to 2.9-A resolution were collected at -150 degrees C from single crystals of Mg-blLAP and native blLAP. Comparisons of omit maps calculated from the Mg-blLAP data with analogous maps calculated from the native blLAP data show electron density in one of the metal binding sites in Mg-blLAP which is much weaker than the electron density in the other binding site. Since there are fewer electrons associated with Mg2+ than with Zn2+, the difference in electron density between the two metal binding sites is consistent with occupancy of the weaker electron density site by Mg2+ and identifies this metal binding site as site 1, defined as the readily exchanging site. The present identification of the metal binding sites reverses the previous presumptive assignment of the metal binding sites which was based on the structure of native blLAP [Burley, S. K., David, P. R., Sweet, R. M., Taylor, A. & Lipscomb, W. N. (1992) J. Mol. Biol. 224, 113-140]. According to the residue-numbering convention of native blLAP, the new assignment of the metal binding sites identifies the readily exchanging site 1 with Zn-488, which is within interaction distance of one side-chain carboxylate oxygen from each of Asp-255, Asp-332, and Glu-334 and the main-chain carbonyl oxygen of Asp-332. The more tightly binding site 2 is identified with Zn-489, which is within interaction distance of one side-chain carboxylate oxygen from each of Asp-255, Asp-273, and Glu-334 and the side-chain amine nitrogen of Lys-250.

PubMed: 8506345
DOI: 10.1073/pnas.90.11.5006

実験手法

X-RAY DIFFRACTION (2.9 Å)