Snapshots of protein folding. A study on the multiple transition state pathway of cytochrome c(551) from Pseudomonas aeruginosa.


Abstract

Cytochrome c(551) (cyt c(551)) from Pseudomonas aeruginosa is a small protein (82 residues) that folds via a three-state pathway with the accumulation in the microsecond time-range of a compact collapsed intermediate. The presence of a single His residue, at position 16, permits the study of the refolding at pH 7.0 in the absence of miscoordination events. Here, we report on folding kinetics in the millisecond time-range as a function of urea under different pH conditions. Analysis of this process (over-and-above proline cis-trans isomerization) at pH 7.0, suggests the existence of a multiple transition state pathway in which we postulate three transition states. Taking advantage of site-directed mutagenesis we propose that the first "unfolded-like" transition state (t(1)) originates from the electrostatic properties of the collapsed state, while the second transition state (t(2)) involves the interaction between the N and C-terminal helices and is stabilized by the salt bridge between Lys10 and Glu70 ( approximately 1 kcal mol(-1)). Our results suggest that, contrary to other cytochromes c, the roll-over effect observed for cyt c(551) at low denaturant concentration can be interpreted in terms of a broad energy barrier without population of any intermediates. The third and more "native-like" transition state (M) can be associated with the breaking/formation of the Fe(3+)-Met61 bond. This strong interaction is stabilized by the hydrogen bond between Trp56 and heme propionate 17 (HP-17) as suggested by the increase in the unfolding rate at high denaturant concentration of the Trp56Phe site-directed mutant. Study holds ProTherm entries: 15966, 15967, 15968, 15969, 15970 Extra Details: stability; folding kinetics; transition states; chevron plot; phi values

Submission Details

ID: 8eNJuUTV

Submitter: Connie Wang

Submission Date: April 24, 2018, 8:46 p.m.

Version: 1

Publication Details
Gianni S;Travaglini-Allocatelli C;CutruzzolĂ  F;Bigotti MG;Brunori M,J. Mol. Biol. (2001) Snapshots of protein folding. A study on the multiple transition state pathway of cytochrome c(551) from Pseudomonas aeruginosa. PMID:11399087
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
2PAC 1993-10-31 SOLUTION STRUCTURE OF FE(II) CYTOCHROME C551 FROM PSEUDOMONAS AERUGINOSA AS DETERMINED BY TWO-DIMENSIONAL 1H NMR
1DVV 2000-11-29 SOLUTION STRUCTURE OF THE QUINTUPLE MUTANT OF CYTOCHROME C-551 FROM PSEUDOMONAS AERUGINOSA
5XEC 2017-08-09 1.1 Heterodimer constructed from PA cyt c551-HT cyt c552 and HT cyt c552-PA cyt c551 chimeric proteins
3X39 2015-04-22 1.5 Domain-swapped dimer of Pseudomonas aeruginosa cytochrome c551
5XED 2017-08-09 1.55 Heterodimer constructed from M61A PA cyt c551-HT cyt c552 and HT cyt c552-PA cyt c551 chimeric proteins
451C 1981-10-02 1.6 STRUCTURE OF CYTOCHROME C551 FROM P. AERUGINOSA REFINED AT 1.6 ANGSTROMS RESOLUTION AND COMPARISON OF THE TWO REDOX FORMS
351C 1981-10-02 1.6 STRUCTURE OF CYTOCHROME C551 FROM P. AERUGINOSA REFINED AT 1.6 ANGSTROMS RESOLUTION AND COMPARISON OF THE TWO REDOX FORMS
2EXV 2006-02-07 1.86 Crystal structure of the F7A mutant of the cytochrome c551 from Pseudomonas aeruginosa

Relevant UniProtKB Entries

Percent Identity Matching Chains Protein Accession Entry Name
100.0 Cytochrome c-551 P00099 CY551_PSEAE