Kinetic characterization of the chemotactic protein from Escherichia coli, CheY. Kinetic analysis of the inverse hydrophobic effect.


CheY, the 129 amino acid chemotactic protein from Escherichia coli, is a good model for studying the folding process of the parallel alpha/beta family of proteins. A study of the folding kinetics of CheY using fluorescence and far-UV circular dichroism (CD) stopped-flow measurements is reported. CheY has three prolines, two of them in the trans conformation and one, Pro110, with a cis Lys-Pro peptide bond. This protein presents a unimolecular, but complex, kinetic mechanism that is dominated by a slow phase compatible with a trans-cis isomerization. Mutation of Pro110 to Gly results in the disappearance of this slow phase, indicating that this cis prolyl bond is responsible for it. The slow phase is catalyzed in a very inefficient way by prolyl isomerase, indicating that the cis bond is poorly accessible to the enzyme during refolding. In agreement with this is the fact that the isomerization of the Lys109-Pro110 bond occurs in an intermediate which contains 96% of the native far-UV CD signal and 80% of the native fluorescence signal. Analysis of the unfolded protein with all its prolines in the native conformation shows the existence of a very stable intermediate in the folding reaction. Mutation of a hyperexposed hydrophobic residue, Phe14, to Asn results in an increase in the free energy of unfolding of the protein of approximately 3 kcal mol-1. Kinetic analysis of the unfolding and refolding reactions of this mutant indicates that the major stabilization effect comes from the relative destabilization of the unfolded state and the kinetic intermediate with respect to the transition state, providing kinetic evidence for the inverse hydrophobic effect. This could also indicate the existence of nonnative interactions in folding intermediates. Study holds ProTherm entries: 317, 318, 2194 Extra Details: Escherichia coli CheY; inverse hydrophobic effect; folding kinetics;,free energies of unfolding; folding intermediates

Submission Details


Submitter: Connie Wang

Submission Date: April 24, 2018, 8:15 p.m.

Version: 1

Publication Details
Muñoz V;Lopez EM;Jager M;Serrano L,Biochemistry (1994) Kinetic characterization of the chemotactic protein from Escherichia coli, CheY. Kinetic analysis of the inverse hydrophobic effect. PMID:8180214
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 Chemotaxis protein CheY P0AE68 CHEY_ECO57
100.0 Chemotaxis protein CheY P0AE67 CHEY_ECOLI
100.0 Chemotaxis protein CheY P0AE69 CHEY_SHIFL
99.2 Chemotaxis protein CheY Q8FGP6 CHEY_ECOL6
97.7 Chemotaxis protein CheY P0A2D6 CHEY_SALTI
97.7 Chemotaxis protein CheY P0A2D5 CHEY_SALTY
94.6 Chemotaxis protein CheY Q9FAD7 CHEY_ENTCL
91.5 Chemotaxis protein CheY Q93P00 CHEY_YEREN
90.7 Chemotaxis protein CheY Q8D0P1 CHEY_YERPE