3m7s | pdb_00003m7s

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

spinqualitylabelsall models 3m7s, resolution 2.40Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 3m7s is a 1 chain structure with sequence from Scadoxus multiflorus. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: ACT, CBI, PO4 Related: 3hu7 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMed 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. Crystal structure determination and inhibition studies of a novel xylanase and alpha-amylase inhibitor protein (XAIP) from Scadoxus multiflorus.,Kumar S, Singh N, Sinha M, Dube D, Singh SB, Bhushan A, Kaur P, Srinivasan A, Sharma S, Singh TP FEBS J. 2010 Jul;277(13):2868-82. Epub 2010 May 27. PMID:20528916 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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