3ICV

Structural Consequences of a Circular Permutation on Lipase B from Candida Antartica

Summary for 3ICV

• Entry DOI: 10.2210/pdb3icv/pdb
• Related: 3ICW
• Descriptor: Lipase B, 2-acetamido-2-deoxy-beta-D-glucopyranose, 2-[BIS-(2-HYDROXY-ETHYL)-AMINO]-2-HYDROXYMETHYL-PROPANE-1,3-DIOL, ... (4 entities in total)
• Functional Keywords: circular permutation, cleavage on pair of basic residues, glycoprotein, hydrolase, lipid degradation, zymogen, disulfide bond
• Biological source: Candida antarctica (Yeast)
• Total number of polymer chains: 1
• Total formula weight: 33550.73

Authors

Horton, J.R.,Qian, Z.,Jia, D.,Lutz, S.,Cheng, X. (deposition date: 2009-07-18, release date: 2009-10-06, Last modification date: 2024-03-13)

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

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: 19683009
DOI: 10.1016/j.jmb.2009.08.008

Experimental method

X-RAY DIFFRACTION (1.49 Å)