1BCX

MUTATIONAL AND CRYSTALLOGRAPHIC ANALYSES OF THE ACTIVE SITE RESIDUES OF THE BACILLUS CIRCULANS XYLANASE

1BCX の概要

• エントリーDOI: 10.2210/pdb1bcx/pdb
• 関連するBIRD辞書のPRD_ID: PRD_900116
• 分子名称: XYLANASE, beta-D-xylopyranose-(1-4)-beta-D-xylopyranose, SULFATE ION, ... (4 entities in total)
• 機能のキーワード: hydrolase(xylan degradation)
• 由来する生物種: Bacillus circulans
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 20761.34

構造登録者

Campbell, R.L.,Wakarchuk, W.W. (登録日: 1994-04-01, 公開日: 1994-10-15, 最終更新日: 2024-02-07)

主引用文献

Wakarchuk, W.W.,Campbell, R.L.,Sung, W.L.,Davoodi, J.,Yaguchi, M.
Mutational and crystallographic analyses of the active site residues of the Bacillus circulans xylanase.
Protein Sci., 3:467-475, 1994

PubMed Abstract: Using site-directed mutagenesis we have investigated the catalytic residues in a xylanase from Bacillus circulans. Analysis of the mutants E78D and E172D indicated that mutations in these conserved residues do not grossly alter the structure of the enzyme and that these residues participate in the catalytic mechanism. We have now determined the crystal structure of an enzyme-substrate complex to 108 A resolution using a catalytically incompetent mutant (E172C). In addition to the catalytic residues, Glu 78 and Glu 172, we have identified 2 tyrosine residues, Tyr 69 and Tyr 80, which likely function in substrate binding, and an arginine residue, Arg 112, which plays an important role in the active site of this enzyme. On the basis of our work we would propose that Glu 78 is the nucleophile and that Glu 172 is the acid-base catalyst in the reaction.

PubMed: 8019418

実験手法

X-RAY DIFFRACTION (1.81 Å)