3vhn

Y61G mutant of Cellulase 12A from thermotoga maritima

spinqualitylabelsall models 3vhn, resolution 2.50Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 3vhn is a 8 chain structure with sequence from Atcc 43589. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: CBI Related: 3amh, 3amm, 3amn, 3amp, 3amq, 3vho, 3vhp Gene: celA (ATCC 43589) Activity: Cellulase, with EC number 3.2.1.4 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Publication Abstract from PubMed Cellulase 12A from Thermotoga maritima (TmCel12A) is a hyperthermostable beta-1,4-endoglucanase. We recently determined the crystal structures of TmCel12A and its complexes with oligosaccharides. Here, by using site-directed mutagenesis, the role played by Arg60 and Tyr61 in a unique surface loop of TmCel12A was investigated. The results are consistent with the previously observed hydrogen bonding and stacking interactions between these two residues and the substrate. Interestingly, the mutant Y61G had the highest activity when compared with the wild-type enzyme and the other mutants. It also shows a wider range of working temperatures than does the wild type, along with retention of the hyperthermostability. The k (cat) and K (m) values of Y61G are both higher than those of the wild type. In conjunction with the crystal structure of Y61G-substrate complex, the kinetic data suggest that the higher endoglucanase activity is probably due to facile dissociation of the cleaved sugar moiety at the reducing end. Additional crystallographic analyses indicate that the insertion and deletion mutations at the Tyr61 site did not affect the overall protein structure, but local perturbations might diminish the substrate-binding strength. It is likely that the catalytic efficiency of TmCel12A is a subtle balance between substrate binding and product release. The activity enhancement by the single mutation of Y61G provides a good example of engineered enzyme for industrial application. Enhanced activity of Thermotoga maritima cellulase 12A by mutating a unique surface loop.,Cheng YS, Ko TP, Huang JW, Wu TH, Lin CY, Luo W, Li Q, Ma Y, Huang CH, Wang AH, Liu JR, Guo RT Appl Microbiol Biotechnol. 2011 Dec 15. PMID:22170108 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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