1trh
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TWO CONFORMATIONAL STATES OF CANDIDA RUGOSA LIPASE
OverviewOverview
The structure of Candida rugosa lipase in a new crystal form has been, determined and refined at 2.1 A resolution. The lipase molecule was found, in an inactive conformation, with the active site shielded from the, solvent by a part of the polypeptide chain-the flap. Comparison of this, structure with the previously determined "open" form of this lipase, in, which the active site is accessible to the solvent and presumably the, substrate, shows that the transition between these 2 states requires only, movement of the flap. The backbone NH groups forming the putative oxyanion, hole do not change position during this rearrangement, indicating that, this feature is preformed in the inactive state. The 2 lipase, conformations probably correspond to states at opposite ends of the, pathway of interfacial activation. Quantitative analysis indicates a large, increase of the hydrophobic surface in the vicinity of the active site., The flap undergoes a flexible rearrangement during which some of its, secondary structure refolds. The interactions of the flap with the rest of, the protein change from mostly hydrophobic in the inactive form to largely, hydrophilic in the "open" conformation. Although the flap movement cannot, be described as a rigid body motion, it has very definite hinge points at, Glu 66 and at Pro 92. The rearrangement is accompanied by a cis-trans, isomerization of this proline, which likely increases the energy required, for the transition between the 2 states, and may play a role in the, stabilization of the active conformation at the water/lipid interface., Carbohydrate attached at Asn 351 also provides stabilization for the open, conformation of the flap.
About this StructureAbout this Structure
1TRH is a Single protein structure of sequence from Candida rugosa with NAG as ligand. Active as Triacylglycerol lipase, with EC number 3.1.1.3 Full crystallographic information is available from OCA.
ReferenceReference
Two conformational states of Candida rugosa lipase., Grochulski P, Li Y, Schrag JD, Cygler M, Protein Sci. 1994 Jan;3(1):82-91. PMID:8142901
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