3abz | pdb_00003abz

Crystal structure of Se-Met labeled Beta-glucosidase from Kluyveromyces marxianus

spinqualitylabelsall models 3abz, resolution 2.15Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 3abz is a 4 chain structure with sequence from Cbs 712. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: GOL NonStd Res: MSE Related: 3ac0 Gene: Bgl, bglI (CBS 712) Activity: Beta-glucosidase, with EC number 3.2.1.21 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 beta-Glucosidase from Kluyveromyces marxianus (KmBglI) belongs to the glycoside hydrolase family 3 (GH3). The enzyme is particularly unusual in that a PA14 domain (pf07691), for which a carbohydrate-binding role has been claimed, is inserted into the catalytic core sequence. Here, we determined the enzymatic properties and crystal structure of KmBglI in complex with glucose at 2.55 A resolution. A striking characteristics of KmBglI was that the enzyme activity is essentially limited to disaccharides, and when trisaccharides were used as the substrates the activity was drastically decreased. This chain length specificity is in sharp contrast to the preferred action on oligosaccharides of barley beta-D-glucan glucohydrolase (ExoI), which does not have a PA14 domain insertion. The structure of subsite (-1) of KmBglI is almost identical to that of Thermotoga neapolitana beta-glucosidase and is also similar to that of ExoI, however, the structures of subsite (+1) significantly differ among them. In KmBglI, the loops extending from the PA14 domain cover the catalytic pocket to form subsite (+1), and hence simultaneously become a steric hindrance that could limit the chain length of the substrates to be accommodated. Mutational studies demonstrated the critical role of the loop regions in determining the substrate specificity. The active site formation mediated by the PA14 domain of KmBglI invokes alpha-complementation of beta-galactosidase exerted by its N-terminal domain, to which the PA14 domain shows structural resemblance. This is the first study that reveals the structural basis of the interaction between the PA14 domain and a carbohydrate. Role of a PA14 domain in determining substrate specificity of a glycoside hydrolase family 3 beta-glucosidase from Kluyveromyces marxianus.,Yoshida E, Hidaka M, Fushinobu S, Koyanagi T, Minami H, Tamaki H, Kitaoka M, Katayama T, Kumagai H Biochem J. 2010 Jul 27. PMID:20662765 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Beta-glucosidase

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