3M7S

Crystal structure of the complex of xylanase GH-11 and alpha amylase inhibitor protein with cellobiose at 2.4 A resolution

3M7S の概要

• エントリーDOI: 10.2210/pdb3m7s/pdb
• 関連するPDBエントリー: 3HU7
• 関連するBIRD辞書のPRD_ID: PRD_900005
• 分子名称: Haementhin, beta-D-glucopyranose-(1-4)-beta-D-glucopyranose, PHOSPHATE ION, ... (5 entities in total)
• 機能のキーワード: tim barrel, protein binding
• 由来する生物種: Scadoxus multiflorus
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 30314.70

構造登録者

Kumar, S.,Dube, D.,Singh, N.,Sinha, M.,Bhushan, A.,Kaur, P.,Sharma, S.,Singh, T.P. (登録日: 2010-03-17, 公開日: 2010-05-05, 最終更新日: 2025-05-07)

主引用文献

Kumar, S.,Singh, N.,Sinha, M.,Dube, D.,Singh, S.B.,Bhushan, A.,Kaur, P.,Srinivasan, A.,Sharma, S.,Singh, T.P.
Crystal structure determination and inhibition studies of a novel xylanase and alpha-amylase inhibitor protein (XAIP) from Scadoxus multiflorus.
Febs J., 277:2868-2882, 2010

PubMed Abstract: A novel plant protein isolated from the underground bulbs of Scadoxus multiflorus, xylanase and alpha-amylase inhibitor protein (XAIP), inhibits two structurally and functionally unrelated enzymes: xylanase and alpha-amylase. The mature protein contains 272 amino acid residues which show sequence identities of 48% to the plant chitinase hevamine and 36% to xylanase inhibitor protein-I, a double-headed inhibitor of GH10 and GH11 xylanases. However, unlike hevamine, it is enzymatically inactive and, unlike xylanase inhibitor protein-I, it inhibits two functionally different classes of enzyme. The crystal structure of XAIP has been determined at 2.0 A resolution and refined to R(cryst) and R(free) factors of 15.2% and 18.6%, respectively. The polypeptide chain of XAIP adopts a modified triosephosphate isomerase barrel fold with eight beta-strands in the inner circle and nine alpha-helices forming the outer ring. The structure contains three cis peptide bonds: Gly33-Phe34, Tyr159-Pro160 and Trp253-Asp254. Although hevamine has a long accessible carbohydrate-binding channel, in XAIP this channel is almost completely filled with the side-chains of residues Phe13, Pro77, Lys78 and Trp253. Solution studies indicate that XAIP inhibits GH11 family xylanases and GH13 family alpha-amylases through two independent binding sites located on opposite surfaces of the protein. Comparison of the structure of XAIP with that of xylanase inhibitor protein-I, and docking studies, suggest that loops alpha3-beta4 and alpha4-beta5 may be involved in the binding of GH11 xylanase, and that helix alpha7 and loop beta6-alpha6 are suitable for the interaction with alpha-amylase.

PubMed: 20528916
DOI: 10.1111/j.1742-4658.2010.07703.x

実験手法

X-RAY DIFFRACTION (2.4 Å)