3vgh

Crystal structure of glycosyltrehalose trehalohydrolase (E283Q) complexed with maltotriosyltrehalose

spinqualitylabelsall models 3vgh, resolution 2.60Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 3vgh is a 1 chain structure with sequence from Saccharolobus solfataricus. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 2.6Å Ligands: FLC, GLC, GOL Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function TREZ_SACSO Publication Abstract from PubMed Glycosyltrehalose trehalohydrolase (GTHase) is an alpha-amylase that cleaves the alpha-1,4 bond adjacent to the alpha-1,1 bond of maltooligosyltrehalose to release trehalose. To investigate the catalytic and substrate recognition mechanisms of GTHase, two residues, Asp252 (nucleophile) and Glu283 (general acid/base), located at the catalytic site of GTHase were mutated (Asp252-->Ser (D252S), Glu (D252E) and Glu283-->Gln (E283Q)), and the activity and structure of the enzyme were investigated. The E283Q, D252E, and D252S mutants showed only 0.04, 0.03, and 0.6% of enzymatic activity against the wild-type, respectively. The crystal structure of the E283Q mutant GTHase in complex with the substrate, maltotriosyltrehalose (G3-Tre), was determined to 2.6-A resolution. The structure with G3-Tre indicated that GTHase has at least five substrate binding subsites and that Glu283 is the catalytic acid, and Asp252 is the nucleophile that attacks the C1 carbon in the glycosidic linkage of G3-Tre. The complex structure also revealed a scheme for substrate recognition by GTHase. Substrate recognition involves two unique interactions: stacking of Tyr325 with the terminal glucose ring of the trehalose moiety and perpendicularly placement of Trp215 to the pyranose rings at the subsites -1 and +1 glucose. Substrate recognition mechanism of a glycosyltrehalose trehalohydrolase from Sulfolobus solfataricus KM1.,Okazaki N, Tamada T, Feese MD, Kato M, Miura Y, Komeda T, Kobayashi K, Kondo K, Blaber M, Kuroki R Protein Sci. 2012 Apr;21(4):539-52. doi: 10.1002/pro.2039. Epub 2012 Feb 28. PMID:22334583 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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