Capping and alpha-helix stability.


Abstract

The first and last four residues of alpha-helices differ from the rest by not being able to make the intrehelical hydrogen bonds between the backbone greater than C=O groups of one turn and the greater than NH groups of the next. Physico-chemical arguments and statistical analysis suggest that there is a preference for certain residues at the C and N termini (The C- and N-caps) that can fulfil the hydrogen bonding requirements. We have tested this hypothesis by constructing a series of mutations in the two N-caps of barnase (Bacillus amyloliquefaciens ribonuclease, positions Thr 6 and Thr 26) and determining the change in their stability. The N-cap is found to stabilize the protein by up to approximately 2.5 kcal mol(-1). The presence of a negative charge of the N-cap adds some 1.6 kcal mol(-1) of stabilization energy because of the interaction with the macroscopic electrostatic dipole of the helix. Study holds ProTherm entries: 1963, 1964, 1965, 1966, 1967, 1968, 1969, 1970, 1971, 1972, 1973, 1974, 1975, 1976 Extra Details: electrostatic dipole; barnase; protein stability;,alpha-helices; hydrogen bonding; physico-chemical

Submission Details

ID: XC84aLHs

Submitter: Connie Wang

Submission Date: April 24, 2018, 8:18 p.m.

Version: 1

Publication Details
Serrano L;Fersht AR,Nature (1989) Capping and alpha-helix stability. PMID:2812029
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
1A2P 1998-01-07T00:00:00+0000 1.5 BARNASE WILDTYPE STRUCTURE AT 1.5 ANGSTROMS RESOLUTION
1B20 1998-12-03T00:00:00+0000 1.7 DELETION OF A BURIED SALT-BRIDGE IN BARNASE
1B21 1998-12-03T00:00:00+0000 2.0 DELETION OF A BURIED SALT BRIDGE IN BARNASE
1B27 1998-12-04T00:00:00+0000 2.1 STRUCTURAL RESPONSE TO MUTATION AT A PROTEIN-PROTEIN INTERFACE
1B2S 1998-11-30T00:00:00+0000 1.82 STRUCTURAL RESPONSE TO MUTATION AT A PROTEIN-PROTEIN INTERFACE
1B2U 1998-12-01T00:00:00+0000 2.1 STRUCTURAL RESPONSE TO MUTATION AT A PROTEIN-PROTEIN INTERFACE
1B2X 1998-12-03T00:00:00+0000 1.8 BARNASE WILDTYPE STRUCTURE AT PH 7.5 FROM A CRYO_COOLED CRYSTAL AT 100K
1B2Z 1998-12-03T00:00:00+0000 2.03 DELETION OF A BURIED SALT BRIDGE IN BARNASE
1B3S 1998-12-01T00:00:00+0000 2.39 STRUCTURAL RESPONSE TO MUTATION AT A PROTEIN-PROTEIN INTERFACE
1BAN 1993-05-19T00:00:00+0000 2.2 THE CONTRIBUTION OF BURIED HYDROGEN BONDS TO PROTEIN STABILITY: THE CRYSTAL STRUCTURES OF TWO BARNASE MUTANTS

Relevant UniProtKB Entries

Percent Identity Matching Chains Protein Accession Entry Name
97.3 Ribonuclease P35078 RN_BACCI
100.0 Ribonuclease P00648 RNBR_BACAM