2EZ7

Carbonic anhydrase activators. Activation of isozymes I, II, IV, VA, VII and XIV with L- and D-histidine and crystallographic analysis of their adducts with isoform II: engineering proton transfer processes within the active site of an enzyme

2EZ7 の概要

• エントリーDOI: 10.2210/pdb2ez7/pdb
• 分子名称: Carbonic anhydrase 2, MERCURY (II) ION, ZINC ION, ... (5 entities in total)
• 機能のキーワード: carbonic anhydrase ii, activators, lyase
• 由来する生物種: Homo sapiens (human)
• 細胞内の位置: Cytoplasm: P00918
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 29711.22

構造登録者

Temperini, C.,Scozzafava, A.,Vullo, D.,Supuran, C.T. (登録日: 2005-11-10, 公開日: 2006-07-18, 最終更新日: 2024-02-14)

主引用文献

Temperini, C.,Scozzafava, A.,Vullo, D.,Supuran, C.T.
Carbonic Anhydrase Activators. Activation of Isozymes I, II, IV, VA, VII, and XIV with L- and D-Histidine and Crystallographic Analysis of Their Adducts with Isoform II: Engineering Proton-Transfer Processes within the Active Site of an Enzyme.
Chemistry, 12:7057-7066, 2006

PubMed Abstract: Activation of six human carbonic anhydrases (CA, EC 4.2.1.1), that is, hCA I, II, IV, VA, VII, and XIV, with l- and d-histidine was investigated through kinetics and by X-ray crystallography. l-His was a potent activator of isozymes I, VA, VII, and XIV, and a weaker activator of hCA II and IV. d-His showed good hCA I, VA, and VII activation properties, being a moderate activator of hCA XIV and a weak activator of hCA II and IV. The structures as determined by X-ray crystallography of the hCA II-l-His/d-His adducts showed the activators to be anchored at the entrance of the active site, contributing to extended networks of hydrogen bonds with amino acid residues/water molecules present in the cavity, explaining their different potency and interaction patterns with various isozymes. The residues involved in l-His recognition were His64, Asn67, Gln92, whereas three water molecules connected the activator to the zinc-bound hydroxide. Only the imidazole moiety of l-His interacted with these amino acids. For the d-His adduct, the residues involved in recognition of the activator were Trp5, His64, and Pro201, whereas two water molecules connected the zinc-bound water to the activator. Only the COOH and NH(2) moieties of d-His participated in hydrogen bonds with these residues. This is the first study showing different binding modes of stereoisomeric activators within the hCA II active site, with consequences for overall proton-transfer processes (rate-determining for the catalytic cycle). The study also points out differences of activation efficiency between various isozymes with structurally related activators, convenient for designing alternative proton-transfer pathways, useful both for a better understanding of the catalytic mechanism and for obtaining pharmacologically useful derivatives, for example, for the management of Alzheimer's disease.

PubMed: 16807956
DOI: 10.1002/chem.200600159

実験手法

X-RAY DIFFRACTION (2 Å)