1g66

ACETYLXYLAN ESTERASE AT 0.90 ANGSTROM RESOLUTION

spinqualitylabelsall models 1g66, resolution 0.90Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 1g66 is a 1 chain structure with sequence from Talaromyces purpureogenus. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 0.9Å Ligands: GOL, SO4 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function AXE2_TALPU Degrades acetylated xylans by cleaving acetyl side groups from the hetero-xylan backbone. 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 Acetylxylan esterase (AXEII; 207 amino acids) from Penicillium purpurogenum has substrate specificities toward acetate esters of d-xylopyranose residues in xylan and belongs to a new class of alpha/beta hydrolases. The crystal structure of AXEII has been determined by single isomorphous replacement and anomalous scattering, and refined at 0.90- and 1.10-A resolutions with data collected at 85 K and 295 K, respectively. The tertiary structure consists of a doubly wound alpha/beta sandwich, having a central six-stranded parallel beta-sheet flanked by two parallel alpha-helices on each side. The catalytic residues Ser(90), His(187), and Asp(175) are located at the C-terminal end of the sheet, an exposed region of the molecule. The serine and histidine side chains in the 295 K structure show the frequently observed conformations in which Ser(90) is trans and the hydroxyl group is in the plane of the imidazole ring of His(187). However, the structure at 85 K displays an additional conformation in which Ser(90) side-chain hydroxyl is away from the plane of the imidazole ring of His(187). The His(187) side chain forms a hydrogen bond with a sulfate ion and adopts an altered conformation. The only other known hydrolase that has a similar tertiary structure is Fusarium solani cutinase. The exposed nature of the catalytic triad suggests that AXEII is a pure esterase, i.e. an alpha/beta hydrolase with specificity for nonlipidic polar substrates. Multiple conformations of catalytic serine and histidine in acetylxylan esterase at 0.90 A.,Ghosh D, Sawicki M, Lala P, Erman M, Pangborn W, Eyzaguirre J, Gutierrez R, Jornvall H, Thiel DJ J Biol Chem. 2001 Apr 6;276(14):11159-66. Epub 2000 Dec 29. PMID:11134051 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Acetylxylan esterase 3D structures

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