Salt-bridges can stabilize but do not accelerate the folding of the homodimeric coiled-coil peptide GCN4-p1.


Double mutant cycle analysis was employed to ascertain the role of intra- and interchain salt-bridges in the folding and stability of the dimeric coiled-coil peptide, GCN4-p1, the 33-residue leucine zipper domain of the transcriptional activator GCN4. Equilibrium circular dichroism studies of the urea-induced unfolding reaction at neutral pH revealed that both types of ionic interactions, localized primarily in the N-terminal portion of the molecule, enhance the stability of the native coiled-coil. By contrast, comparable stopped-flow circular dichroism studies indicate that the salt-bridge interactions, with one possible exception, are not well formed in the transition state for folding. Although the E22Q/R25A double mutant failed to fold, fragmentation studies suggest that the E22/R25 intramolecular salt-bridge may play a critical role in stabilizing C-terminal nascent helices that drive the association reaction. The remaining salt-bridges appear to stabilize the parallel-stranded coiled-coil architecture of GCN4-p1 only after the peptide traverses the rate-limiting, dimeric transition state. Study holds ProTherm entries: 17015, 17016, 17017, 17018, 17019, 17020, 17021, 17022, 17023, 17024, 17025, 17026, 17027, 17028, 17029 Extra Details: Pseudo wild type M2V. circular dichroism spectroscopy; electrostatics; ionic interactions; leucine zipper peptides; protein folding kinetics

Submission Details

ID: ZaCckz9Q

Submitter: Connie Wang

Submission Date: April 24, 2018, 8:49 p.m.

Version: 1

Publication Details
Ibarra-Molero B;Zitzewitz JA;Matthews CR,J. Mol. Biol. (2004) Salt-bridges can stabilize but do not accelerate the folding of the homodimeric coiled-coil peptide GCN4-p1. PMID:15037063
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 UniProtKB Entries

Percent Identity Matching Chains Protein Accession Entry Name
100.0 General control protein GCN4 P03069 GCN4_YEAST