PDBsum entry 3btf

Hydrolase/hydrolase inhibitor

PDB id: 3btf

Contents

Protein chains

223 a.a. *

56 a.a. *

Ligands

SO4 ×4

Metals

_CA

Waters ×131

* Residue conservation analysis

PDB id:

3btf

Name:

Hydrolase/hydrolase inhibitor

Title:

The crystal structures of the complexes between bovine beta-trypsin and ten p1 variants of bpti.

Structure:

Protein (trypsin). Chain: e. Protein (pancreatic trypsin inhibitor). Chain: i. Engineered: yes. Mutation: yes

Source:

Bos taurus. Cattle. Organism_taxid: 9913. Expressed in: escherichia coli. Expression_system_taxid: 562

Biol. unit:

Octamer (from PQS)

Resolution:

1.80Å R-factor: 0.194 R-free: 0.225

Authors:

R.Helland,J.Otlewski,O.Sundheim,M.Dadlez,A.O.Smalas

Key ref:

R.Helland et al. (1999). The crystal structures of the complexes between bovine beta-trypsin and ten P1 variants of BPTI. J Mol Biol, 287, 923-942. PubMed id: 10222201 DOI: 10.1006/jmbi.1999.2654

Date:

10-Mar-99 Release date: 13-Mar-00

Protein chain

P00760  (TRY1_BOVIN) -  Serine protease 1 from Bos taurus

Seq: 246 a.a.

Struc: 223 a.a.

Protein chain

P00974  (BPT1_BOVIN) -  Pancreatic trypsin inhibitor from Bos taurus

Seq: 100 a.a.

Struc: 56 a.a.*

* PDB and UniProt seqs differ at 2 residue positions (black crosses)

Enzyme reactions

• Enzyme class: Chain E: E.C.3.4.21.4 - trypsin.
• Reaction: Preferential cleavage: Arg-|-Xaa, Lys-|-Xaa.

DOI no: 10.1006/jmbi.1999.2654

J Mol Biol 287:923-942 (1999)

PubMed id: 10222201

The crystal structures of the complexes between bovine beta-trypsin and ten P1 variants of BPTI.

R.Helland, J.Otlewski, O.Sundheim, M.Dadlez, A.O.Smalås.

ABSTRACT

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.

Selected figure(s)

Figure 7.
Figure 7. Superimposition of the P1-S1 binding sites of typsin-BPTI complexes of (a) P 1 Asp (red) and P1 Glu (blue) and (b) of P1 Glu (blue) and P1 Gln (green). The P1 side-chains of Glu and Gln are both shown with two alternate conformations. The Figure was produced using BOBSCRIPT (Kraulis 1991; Esnouf, 1997).

Figure 8.
Figure 8. Superimposition of the P1-S1 binding sites of trypsin-BPTI complexes with P 1 Trp (red), P1 Phe (green) and P1 His (blue). The Figure was produced using BOBSCRIPT (Kraulis 1991; Esnouf, 1997).

The above figures are reprinted by permission from Elsevier: J Mol Biol (1999, 287, 923-942) copyright 1999.

Figures were selected by an automated process.