4k6k

Crystal structure of CALB mutant D223G from Candida antarctica

spinqualitylabelsall models 4k6k, resolution 1.60Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 4k6k is a 2 chain structure with sequence from Moesziomyces antarcticus. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 1.6Å Ligands: EDO Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function LIPB_PSEA2 Hydrolysis of triglycerides. Is very stereospecific both in hydrolysis and in organic synthesis and has a potentially important application in glucolipid synthesis. Publication Abstract from PubMed Enzyme stability is an important issue for protein engineers. Understanding how rigidity in the active site affects protein kinetic stability will provide new insight into enzyme stabilization. In this study, we demonstrated enhanced kinetic stability of Candida antarctica lipase B (CalB) by mutating the structurally flexible residues within the active site. Six residues within 10 A of the catalytic Ser(105) residue with a high B factor were selected for iterative saturation mutagenesis. After screening 2200 colonies, we obtained the D223G/L278M mutant, which exhibited a 13-fold increase in half-life at 48 degrees C and a 12 degrees C higher T50(15), the temperature at which enzyme activity is reduced to 50% after a 15-min heat treatment. Further characterization showed that global unfolding resistance against both thermal and chemical denaturation also improved. Analysis of the crystal structures of wild-type CalB and the D223G/L278M mutant revealed that the latter formed an extra main chain hydrogen bond network with seven structurally coupled residues within the flexible alpha10 helix that are primarily involved in forming the active site. Further investigation of the relative B factor profile and molecular dynamics simulation confirmed that the enhanced rigidity decreased fluctuation of the active site residues at high temperature. These results indicate that enhancing the rigidity of the flexible segment within the active site may provide an efficient method for improving enzyme kinetic stability. Enhanced enzyme kinetic stability by increasing rigidity within the active site.,Xie Y, An J, Yang G, Wu G, Zhang Y, Cui L, Feng Y J Biol Chem. 2014 Mar 14;289(11):7994-8006. doi: 10.1074/jbc.M113.536045. Epub, 2014 Jan 21. PMID:24448805 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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