3ICW
Structure of a Circular Permutation on Lipase B from Candida Antartica with Bound Suicide Inhibitor
Summary for 3ICW
| Entry DOI | 10.2210/pdb3icw/pdb |
| Related | 3ICV |
| Descriptor | Lipase B, 2-acetamido-2-deoxy-beta-D-glucopyranose, PHOSPHATE ION, ... (5 entities in total) |
| Functional Keywords | circular permutation, suicide inhibition, hydrolase, cleavage on pair of basic residues, disulfide bond, glycoprotein, lipid degradation, zymogen |
| Biological source | Candida antarctica (Yeast) |
| Total number of polymer chains | 1 |
| Total formula weight | 33616.64 |
| Authors | Horton, J.R.,Qian, Z.,Jia, D.,Lutz, S.A.,Cheng, X. (deposition date: 2009-07-18, release date: 2009-10-06, Last modification date: 2024-11-20) |
| Primary citation | Qian, Z.,Horton, J.R.,Cheng, X.,Lutz, S. Structural redesign of lipase B from Candida antarctica by circular permutation and incremental truncation. J.Mol.Biol., 393:191-201, 2009 Cited by PubMed Abstract: Circular permutation of Candida antarctica lipase B yields several enzyme variants with substantially increased catalytic activity. To better understand the structural and functional consequences of protein termini reorganization, we have applied protein engineering and x-ray crystallography to cp283, one of the most active hydrolase variants. Our initial investigation has focused on the role of an extended surface loop, created by linking the native N- and C-termini, on protein integrity. Incremental truncation of the loop partially compensates for observed losses in secondary structure and the permutants' temperature of unfolding. Unexpectedly, the improvements are accompanied by quaternary-structure changes from monomer to dimer. The crystal structures of one truncated variant (cp283 Delta 7) in the apo-form determined at 1.49 A resolution and with a bound phosphonate inhibitor at 1.69 A resolution confirmed the formation of a homodimer by swapping of the enzyme's 35-residue N-terminal region. Separately, the new protein termini at amino acid positions 282/283 convert the narrow access tunnel to the catalytic triad into a broad crevice for accelerated substrate entry and product exit while preserving the native active-site topology for optimal catalytic turnover. PubMed: 19683009DOI: 10.1016/j.jmb.2009.08.008 PDB entries with the same primary citation |
| Experimental method | X-RAY DIFFRACTION (1.69 Å) |
Structure validation
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