2C0H

X-ray structure of beta-mannanase from blue mussel Mytilus edulis

2C0H の概要

• エントリーDOI: 10.2210/pdb2c0h/pdb
• 分子名称: MANNAN ENDO-1,4-BETA-MANNOSIDASE, SULFATE ION (3 entities in total)
• 機能のキーワード: mytilus edulis, hydrolase, tim alpha/beta barrel
• 由来する生物種: MYTILUS EDULIS (BLUE MUSSEL)
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 39686.92

構造登録者

Larsson, A.M.,Anderson, L.,Xu, B.,Munoz, I.G.,Uson, I.,Janson, J.-C.,Stalbrand, H.,Stahlberg, J. (登録日: 2005-09-02, 公開日: 2006-02-22, 最終更新日: 2024-05-08)

主引用文献

Larsson, A.M.,Anderson, L.,Xu, B.,Munoz, I.G.,Uson, I.,Janson, J.-C.,Stalbrand, H.,Stahlberg, J.
Three-Dimensional Crystal Structure and Enzymic Characterization of Beta-Mannanase Man5A from Blue Mussel Mytilus Edulis.
J.Mol.Biol., 357:1500-, 2006

PubMed Abstract: Endo-beta-1,4-d-mannanase is the key depolymerizing enzyme for beta-1,4-mannan polymers present in the cell walls of plants and some algae, as well as in some types of plant seeds. Endo-1,4-beta-mannanase from blue mussel Mytilus edulis (MeMan5A) belongs to the glycoside hydrolase (GH) family 5 enzymes. The MeMan5A structure has been determined to 1.6A resolution using the multiple-wavelength anomalous dispersion method at the selenium K edge with selenomethionyl MeMan5A expressed in the yeast Pichia pastoris. As expected for GH 5 enzymes, the structure showed a (betaalpha)(8)-barrel fold. An unusually large number of histidine side-chains are exposed on the surface, which may relate to its location within the crystalline style of the digestive tract of the mussel. Kinetic analysis of MeMan5A revealed that the enzyme requires at least six subsites for efficient hydrolysis. Mannotetraose (M4) and mannopentaose (M5) were shown to interact with subsites -3 to +1, and -3 to +2, respectively. A clear kinetic threshold was observed when going from M4 to M5, indicating that the +2 subsite provides important interaction in the hydrolysis of short oligomeric mannose substrates. The catalytic centre motif at subsite -1 found in superfamily GH clan A is, as expected, conserved in MeMan5A, but the architecture of the catalytic cleft differs significantly from other GH 5 enzyme structures. We therefore suggest that MeMan5A represents a new subfamily in GH 5.

PubMed: 16487541
DOI: 10.1016/J.JMB.2006.01.044

実験手法

X-RAY DIFFRACTION (1.6 Å)