Guanidine hydrochloride-induced denaturation of the colicin E1 channel peptide: unfolding of local segments using genetically substituted tryptophan residues.


Abstract

The soluble colicin E1 channel peptide has a roughly spherical, highly alpha-helical, compact structure. The structural unfolding properties of the colicin E1 channel peptide were analyzed using fluorescence techniques. The guanidine hydrochloride-induced unfolding pattern of the wild-type channel peptide was examined by monitoring intrinsic tryptophan fluorescence. Additionally, peptide unfolding was examined with the fluorophore, 1-anilinonaphthalene-8-sulfonic acid. In order to probe the unfolding of local segments, single-tryptophan channel peptides were constructed by site-directed mutagenesis. Shifts in fluorescence emission maxima of the single tryptophan residues were used to monitor site-specific unfolding events, in the presence of guanidine hydrochloride. The unfolding patterns reported by tryptophans in different regions of the peptide were diverse. The concentration of guanidine hydrochloride at the unfolding transition midpoint for each mutant peptide and the free energy of unfolding were calculated in order to estimate local segment stabilities. Also, secondary structure unfolding was monitored using circular dichroism spectroscopy. The results of unfolding analysis showed that the channel peptide's unfolding mechanism involves an intermediate structure stabilized by the C-terminal hydrophobic core of the peptide. Knowledge of the unfolding pattern of the soluble channel peptide will aid in the understanding of the secondary and tertiary structural interactions within the channel peptide and the mechanism of colicin E1 activation. Study holds ProTherm entries: 5101 Extra Details:

Submission Details

ID: eZnbM2nK4

Submitter: Connie Wang

Submission Date: April 24, 2018, 8:28 p.m.

Version: 1

Publication Details
Steer BA;Merrill AR,Biochemistry (1995) Guanidine hydrochloride-induced denaturation of the colicin E1 channel peptide: unfolding of local segments using genetically substituted tryptophan residues. PMID:7766633
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
2I88 2006-09-26 2.5 Crystal structure of the Channel-forming Domain of Colicin E1

Relevant UniProtKB Entries

Percent Identity Matching Chains Protein Accession Entry Name
100.0 Colicin-E1 P02978 CEA1_ECOLX