1CZ1

EXO-B-(1,3)-GLUCANASE FROM CANDIDA ALBICANS AT 1.85 A RESOLUTION

1CZ1 の概要

• エントリーDOI: 10.2210/pdb1cz1/pdb
• 分子名称: PROTEIN (EXO-B-(1,3)-GLUCANASE) (2 entities in total)
• 機能のキーワード: exoglucanase, candida albicans, glycoside hydrolase family 5, hydrolase
• 由来する生物種: Candida albicans
• 細胞内の位置: Secreted, cell wall : P29717
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 45269.88

構造登録者

Cutfield, S.M.,Davies, G.J.,Murshudov, G.,Anderson, B.F.,Moody, P.C.E.,Sullivan, P.A.,Cutfield, J.F. (登録日: 1999-09-01, 公開日: 2000-01-03, 最終更新日: 2024-10-30)

主引用文献

Cutfield, S.M.,Davies, G.J.,Murshudov, G.,Anderson, B.F.,Moody, P.C.,Sullivan, P.A.,Cutfield, J.F.
The structure of the exo-beta-(1,3)-glucanase from Candida albicans in native and bound forms: relationship between a pocket and groove in family 5 glycosyl hydrolases.
J.Mol.Biol., 294:771-783, 1999

PubMed Abstract: A group of fungal exo-beta-(1,3)-glucanases, including that from the human pathogen Candida albicans (Exg), belong to glycosyl hydrolase family 5 that also includes many bacterial cellulases (endo-beta-1, 4-glucanases). Family members, despite wide sequence variations, share a common mechanism and are characterised by possessing eight invariant residues making up the active site. These include two glutamate residues acting as nucleophile and acid/base, respectively. Exg is an abundant secreted enzyme possessing both hydrolase and transferase activity consistent with a role in cell wall glucan metabolism and possibly morphogenesis. The structures of Exg in both free and inhibited forms have been determined to 1.9 A resolution. A distorted (beta/alpha)8 barrel structure accommodates an active site which is located within a deep pocket, formed when extended loop regions close off a cellulase-like groove. Structural analysis of a covalently bound mechanism-based inhibitor (2-fluoroglucosylpyranoside) and of a transition-state analogue (castanospermine) has identified the binding interactions at the -1 glucose binding site. In particular the carboxylate of Glu27 serves a dominant hydrogen-bonding role. Access by a 1,3-glucan chain to the pocket in Exg can be understood in terms of a change in conformation of the terminal glucose residue from chair to twisted boat. The geometry of the pocket is not, however, well suited for cleavage of 1,4-glycosidic linkages. A second glucose site was identified at the entrance to the pocket, sandwiched between two antiparallel phenylalanine side-chains. This aromatic entrance-way must not only direct substrate into the pocket but also may act as a clamp for an acceptor molecule participating in the transfer reaction.

PubMed: 10610795
DOI: 10.1006/jmbi.1999.3287

実験手法

X-RAY DIFFRACTION (1.85 Å)