PDBsum entry 1jv8

Blood clotting

PDB id: 1jv8

Contents

Protein chain

58 a.a. *

* Residue conservation analysis

PDB id:

1jv8

Name:

Blood clotting

Title:

Nmr structure of bpti mutant g37a

Structure:

Trypsin inhibitor. Chain: a. Engineered: yes. Mutation: yes

Source:

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

NMR struc:

23 models

Authors:

J.L.Battiste,R.Li,C.Woodward

Key ref:

J.L.Battiste et al. (2002). A highly destabilizing mutation, G37A, of the bovine pancreatic trypsin inhibitor retains the average native conformation but greatly increases local flexibility. Biochemistry, 41, 2237-2245. PubMed id: 11841215 DOI: 10.1021/bi011693e

Date:

28-Aug-01 Release date: 12-Sep-01

Protein chain

P00974  (BPT1_BOVIN) -  Pancreatic trypsin inhibitor from Bos taurus

Seq: 100 a.a.

Struc: 58 a.a.*

* PDB and UniProt seqs differ at 1 residue position (black cross)

DOI no: 10.1021/bi011693e

Biochemistry 41:2237-2245 (2002)

PubMed id: 11841215

A highly destabilizing mutation, G37A, of the bovine pancreatic trypsin inhibitor retains the average native conformation but greatly increases local flexibility.

J.L.Battiste, R.Li, C.Woodward.

ABSTRACT

A point mutation, G37A, on the surface of bovine pancreatic trypsin inhibitor (BPTI) destabilizes the protein by approximately 5 kcal/mol, which is very high for addition of one methyl group. In wild-type (WT) BPTI, Gly 37 HN is in an unusual NH-aromatic-NH network of interactions with the ring of Tyr 35 and the side chain HN of Asn 44. G37A was designed to disrupt this interaction, since the phi and psi backbone angles of G37 are not favorable for an amino acid containing a beta-carbon. Investigations of the structure and dynamics by NMR methods show that G37A retains the average WT structure. The NH-aromatic-NH interactions remain intact, as indicated by NOEs and the large upfield ring current shift (approximately 4 ppm) of A37 HN. The NMR structure, confirmed by molecular modeling calculations, requires phi and psi backbone angles that are highly destabilizing when alanine is in position 37. Although the average structure is essentially unchanged, the dynamics are altered dramatically. Many residues in the region of the mutation have increased flexibility, as probed by aromatic ring flip rates and native state hydrogen exchange. We conclude that a large fraction of the destabilization arises from maintaining A37 in a high-energy conformation. This suggests that disruption of the NH-aromatic-NH network is energetically very costly, and may involve other cooperatively linked interactions. The results illustrate the importance of the Gly-Gly sequence at positions 36 and 37 and the 37 HN-35 aromatic interaction to the stability, folding, and dynamics of the BPTI.