Mutational analysis of the N-capping box of the alpha-helix of chymotrypsin inhibitor 2.


Abstract

The N-terminus of the helix of the chymotrypsin inhibitor 2 from barley (CI2) has an N-capping box (Ser at the first position in the helix and Glu at position 4) as well as a frequently found Glu at position 3. The energetic importance of this motif has been studied by determining the free energy of unfolding of the wild-type and protein mutants derived from those residues using guanidinium chloride-induced denaturation and differential scanning microcalorimetry. Mutating N-cap residue Ser31 to either Ala or Gly destabilizes CI2 by 0.8-1 kcal mol-1. Truncation of the box in the mutants SA31EA33EA34 or SG31EA33EA34 destablizes the protein by 1.5-2 kcal mol-1. The N-capping box is an important motif in stabilizing proteins and delineating the beginning of alpha-helices in the pathway of protein folding. Study holds ProTherm entries: 9801, 9802, 9803, 9804, 9805, 9806, 9807, 9808, 9809, 9810, 9811, 9812, 9813, 9814, 9815, 9816, 9817, 9818, 9819, 9820, 9821, 9822, 9823, 9824 Extra Details: helix stability; N-cap; protein folding; protein stability

Submission Details

ID: rE7YZdVA4

Submitter: Connie Wang

Submission Date: April 24, 2018, 8:38 p.m.

Version: 1

Publication Details
elMasry NF;Fersht AR,Protein Eng. (1994) Mutational analysis of the N-capping box of the alpha-helix of chymotrypsin inhibitor 2. PMID:7937708
Additional Information

Structure view and single mutant data analysis

Study data

No weblogo for data of varying length.
Colors: D E R H K S T N Q A V I L M F Y W C G P
 

Data Distribution

Studies with similar sequences (approximate matches)

Correlation with other assays (exact sequence matches)


Relevant PDB Entries

Structure ID Release Date Resolution Structure Title
1CIQ 1995-10-02T00:00:00+0000 2.2 COMPLEX OF TWO FRAGMENTS OF CI2, RESIDUES 1-40 AND 41-64
1CIQ 1995-10-02T00:00:00+0000 2.2 COMPLEX OF TWO FRAGMENTS OF CI2, RESIDUES 1-40 AND 41-64
1CIR 1995-10-02T00:00:00+0000 0 COMPLEX OF TWO FRAGMENTS OF CI2 [(1-40)(DOT)(41-64)]
1CIR 1995-10-02T00:00:00+0000 0 COMPLEX OF TWO FRAGMENTS OF CI2 [(1-40)(DOT)(41-64)]
1CIS 1993-04-23T00:00:00+0000 0 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
1COA 1993-05-14T00:00:00+0000 2.2 THE EFFECT OF CAVITY CREATING MUTATIONS IN THE HYDROPHOBIC CORE OF CHYMOTRYPSIN INHIBITOR 2
1CQ4 1998-11-17T00:00:00+0000 1.8 CI2 MUTANT WITH TETRAGLUTAMINE (MGQQQQGM) REPLACING MET59
1CQ4 1998-11-17T00:00:00+0000 1.8 CI2 MUTANT WITH TETRAGLUTAMINE (MGQQQQGM) REPLACING MET59
1LW6 2002-05-30T00:00:00+0000 1.5 Crystal Structure of the Complex of Subtilisin BPN' with Chymotrypsin Inhibitor 2 at 1.5 Angstrom Resolution
1YPA 1993-01-10T00:00:00+0000 2.0 DIRECT OBSERVATION OF BETTER HYDRATION AT THE N-TERMINUS OF AN ALPHA-HELIX WITH GLYCINE RATHER THAN ALANINE AS N-CAP

Relevant UniProtKB Entries

Percent Identity Matching Chains Protein Accession Entry Name
100.0 Subtilisin-chymotrypsin inhibitor-2A P01053 ICI2_HORVU
92.6 Subtilisin-chymotrypsin inhibitor-2A P08626 ICI3_HORVU