3btf

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spinqualitylabelsall models 3btf, resolution 1.8Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image

THE CRYSTAL STRUCTURES OF THE COMPLEXES BETWEEN BOVINE BETA-TRYPSIN AND TEN P1 VARIANTS OF BPTI.

Overview

The high-resolution X-ray structures have been determined for ten, complexes formed between bovine beta-trypsin and P1 variants (Gly, Asp, Glu, Gln, Thr, Met, Lys, His, Phe, Trp) of bovine pancreatic trypsin, inhibitor (BPTI). All the complexes were crystallised from the same, conditions. The structures of the P1 variants Asp, Glu, Gln and Thr, are, reported here for the first time in complex with any serine proteinase., The resolution of the structures ranged from 1.75 to 2.05 A and the, R-factors were about 19-20 %. The association constants of the mutants, ranged from 1.5x10(4) to 1.7x10(13) M-1. All the structures could be, fitted into well-defined electron density, and all had very similar global, conformations. All the P1 mutant side-chains could be accomodated at the, primary binding site, but relative to the P1 Lys, there were small local, changes within the P1-S1 interaction site. These comprised: (1) changes in, the number and dynamics of water molecules inside the pocket; (2) multiple, conformations and non-optimal dihedral angles for some of the P1, side-chains, Ser190 and Gln192; and (3) changes in temperature factors of, the pocket walls as well as the introduced P1 side-chain. Binding of the, cognate P1 Lys is characterised by almost optimal dihedral angles, hydrogen bonding distances and angles, in addition to considerably lower, temperature factors. Thus, the trypsin S1 pocket seems to be designed, particularly for lysine binding.

About this Structure

3BTF is a Protein complex structure of sequences from Bos taurus with CA and SO4 as ligands. Active as Trypsin, with EC number 3.4.21.4 Full crystallographic information is available from OCA.

Reference

The crystal structures of the complexes between bovine beta-trypsin and ten P1 variants of BPTI., Helland R, Otlewski J, Sundheim O, Dadlez M, Smalas AO, J Mol Biol. 1999 Apr 16;287(5):923-42. PMID:10222201

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