PDBsum entry 1cis

Hybrid protein

PDB id: 1cis

Contents

Protein chain

66 a.a. *

* Residue conservation analysis

PDB id:

1cis

Name:

Hybrid protein

Title:

Context dependence of protein secondary structure formation. The three-dimensional structure and stability of a hybrid between chymotrypsin inhibitor 2 and helix e from subtilisin carlsberg

Structure:

Hybrid protein formed from chymotrypsin inhibitor-2. Chain: a. Engineered: yes

Source:

Hordeum vulgare, bacillus licheniformis. Barley, denitrobacillus licheniformis. Organism_taxid: 4513, 1402. Expressed in: escherichia coli. Expression_system_taxid: 562

NMR struc:

15 models

Authors:

P.Osmark,P.Sorensen,F.M.Poulsen

Key ref:

P.Osmark et al. (1993). Context dependence of protein secondary structure formation: the three-dimensional structure and stability of a hybrid between chymotrypsin inhibitor 2 and helix E from subtilisin Carlsberg. Biochemistry, 32, 11007-11014. PubMed id: 8218165 DOI: 10.1021/bi00092a009

Date:

23-Apr-93 Release date: 31-Oct-93

Protein chain

P01053  (ICI2_HORVU) -  Subtilisin-chymotrypsin inhibitor-2A from Hordeum vulgare

Seq: 84 a.a.

Struc: 66 a.a.*

* PDB and UniProt seqs differ at 12 residue positions (black crosses)

Enzyme reactions

• Enzyme class: E.C.?

DOI no: 10.1021/bi00092a009

Biochemistry 32:11007-11014 (1993)

PubMed id: 8218165

Context dependence of protein secondary structure formation: the three-dimensional structure and stability of a hybrid between chymotrypsin inhibitor 2 and helix E from subtilisin Carlsberg.

P.Osmark, P.Sørensen, F.M.Poulsen.

ABSTRACT

The loop region of chymotrypsin inhibitor 2 from barley has been employed as a scaffold for testing the intrinsic propensity of a peptide fragment to form a secondary structure. The helix formation of the nine amino acid residue segment Lys-Gln-Ala-Val-Asp-Asn-Ala-Tyr-Ala of helix E from subtilisin Carlsberg has been studied by the construction of a hybrid consisting of chymotrypsin inhibitor 2 (CI2) where part of the active loop has been replaced by the nonapeptide. An expression system for a truncated form of CI2 where the 19 structureless residues of the N-terminus have been removed and Leu20 replaced by methionyl was constructed from the entire 83-residue wild-type CI2 gene by polymerase chain reaction methodology. The gene encoding the hybrid was constructed from the truncated inhibitor gene. The stability of the truncated inhibitor and of the hybrid toward guanidinium chloride denaturation was examined. From these measurements, the energy of unfolding in pure water was extrapolated to 30.5 +/- 1.0 kJ/mol for the truncated inhibitor and 10.9 +/- 0.3 kJ/mol for the hybrid. These energies show that the stability of CI2 is unaffected by the N-terminal truncation but severely decreased by the loop mutations. The three-dimensional structure of the hybrid protein has been determined in solution by nuclear magnetic resonance spectroscopy using 893 distance restraints and 84 torsional angle restraints. The average root-mean-square deviation (rmsd) of 15 structures compared to their geometrical average was 0.8 +/- 0.2 A for heavy backbone atoms and 1.3 +/- 0.2 A for all heavy atoms.(ABSTRACT TRUNCATED AT 250 WORDS)