1ejm

CRYSTAL STRUCTURE OF THE BPTI ALA16LEU MUTANT IN COMPLEX WITH BOVINE TRYPSIN

spinqualitylabelsall models 1ejm, resolution 1.85Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 1ejm is a 6 chain structure with sequence from Bos taurus. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: SO4 Activity: Trypsin, with EC number 3.4.21.4 Resources: FirstGlance, OCA, RCSB, PDBsum Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMed The role of the S(1) subsite in trypsin, chymotrypsin and plasmin has been examined by measuring the association with seven different mutants of bovine pancreatic trypsin inhibitor (BPTI); the mutants contain Gly, Ala, Ser, Val, Leu, Arg, and Trp at the P(1) position of the reactive site. The effects of substitutions at the P(1) position on the association constants are very large, comprising seven orders of magnitude for trypsin and plasmin, and over five orders for chymotrypsin. All mutants showed a decrease of the association constant to the three proteinases in the same order: Ala>Gly>Ser>Arg>Val>Leu>Trp. Calorimetric and circular dichroism methods showed that none of the P1 substitutions, except the P1-Val mutant, lead to destabilisation of the binding loop conformation. The X-ray structure of the complex formed between bovine beta-trypsin and P(1)-Leu BPTI showed that the P(1)-Leu sterically conflicts with the side-chain of P(3)-Ile, which thereby is forced to rotate approximately 90 degrees. Ile18 (P(3)) in its new orientation, in turn interacts with the Tyr39 side-chain of trypsin. Introduction of a large side-chain at the P1' position apparently leads to a cascade of small alterations of the trypsin-BPTI interface that seem to destabilise the complex by it adopting a less optimized packing and by tilting the BPTI molecule up to 15 degrees compared to the native trypsin-BPTI complex. Substitutions at the P(1) position in BPTI strongly affect the association energy with serine proteinases.,Grzesiak A, Helland R, Smalas AO, Krowarsch D, Dadlez M, Otlewski J J Mol Biol. 2000 Aug 4;301(1):205-17. PMID:10926503 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Basic Pancreatic Trypsin Inhibitor Trypsin

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