PDBsum entry 1bhc

Protease inhibitor

PDB id: 1bhc

Contents

Protein chains

(+ 4 more) 56 a.a. *

Ligands

SCN ×10

Waters ×118

* Residue conservation analysis

PDB id:

1bhc

Name:

Protease inhibitor

Title:

Bovine pancreatic trypsin inhibitor crystallized from thiocyanate

Structure:

Bovine pancreatic trypsin inhibitor. Chain: a, b, c, d, e, f, g, h, i, j. Synonym: bpti

Source:

Bos taurus. Cattle. Organism_taxid: 9913. Organ: pancreas

Biol. unit:

Decamer (from PQS)

Resolution:

2.70Å R-factor: 0.201 R-free: 0.265

Authors:

C.Hamiaux,T.Prange

Key ref:

C.Hamiaux et al. (1999). The decameric structure of bovine pancreatic trypsin inhibitor (BPTI) crystallized from thiocyanate at 2.7 A resolution. Acta Crystallogr D Biol Crystallogr, 55, 103-113. PubMed id: 10089400 DOI: 10.1107/S0907444998008725

Date:

05-Jun-98 Release date: 16-Sep-98

Protein chains

P00974  (BPT1_BOVIN) -  Pancreatic trypsin inhibitor from Bos taurus

Seq: 100 a.a.

Struc: 56 a.a.

DOI no: 10.1107/S0907444998008725

Acta Crystallogr D Biol Crystallogr 55:103-113 (1999)

PubMed id: 10089400

The decameric structure of bovine pancreatic trypsin inhibitor (BPTI) crystallized from thiocyanate at 2.7 A resolution.

C.Hamiaux, T.Prangé, M.Riès-Kautt, A.Ducruix, S.Lafont, J.P.Astier, S.Veesler.

ABSTRACT

The structure of a monoclinic form of bovine pancreatic trypsin inhibitor (BPTI) crystallized from a thiocyanate solution has been determined and refined at 2.7 A resolution. The space group is P21 with a = 71.56, b = 73.83, c = 64.47 A, beta = 93.9 degrees and Z = 20. The ten independent molecules were located by a multi-body molecular-replacement search as developed in the AMoRe program, starting from a single monomer model (PDB code: 6PTI). The molecular arrangement of the subunits is a decamer resulting from the combination of two orthogonal fivefold and twofold non-crystallographic axes. This builds a globular micelle-like particle which minimizes hydrophobic interactions with the solvent. The refinement was conducted with non-crystallographic symmetry constraints up to a final residual of R = 0.20 (Rfree= 0.26). The root-mean-square deviations from ideal geometry were 0.015 A and 1.6 degrees on bond distances and bond angles, respectively. Several sites for thiocyanate ions were analyzed.

Selected figure(s)

Figure 5.
Figure 5 Least-squares fit of C chains of the ten subunits of the decamer, plus the three structures 4PTI, 5PTI and 6PTI crystallized in phosphate. The locations of the binding zones of thiocyanates are indicated by dashed circles with respect to this common target molecule. The two phosphate anions of 5PTI and 6PTI structures are also reported - they correspond to the anionic site 1. Due to non-crystallographic symmetry considerations, the three anionic sites correspond to four different binding zones. Site 1 and site 1' are equivalent within each pentamer (molecules SCN1-SCN3) e.g. thiocyanate-labelled SCN1 lies in site 1 for subunit G and in site 1' for subunit F. Site 3 (SCN4-SCN7) is in the vicinity of residues 47-49 of dimers A/F, B/J, C/I and E/G, while site 4 (SCN8-SCN10) connects pairs of Lys46 from two different pentamers: D/I, B/F and H/E.

Figure 7.
Figure 7 The surface of the BPTI decamer: the particle adopts a micellar structure with most of the positively charged residues pointing outwards and hydrophobic residues turned inside.

The above figures are reprinted by permission from the IUCr: Acta Crystallogr D Biol Crystallogr (1999, 55, 103-113) copyright 1999.

Figures were selected by an automated process.