A stability transition at mildly acidic pH in the alpha-hemolysin (alpha-toxin) from Staphylococcus aureus.


Abstract

The effects of mildly acidic conditions on the free energy of unfolding (DeltaG(u)(buff)) of the pore-forming alpha-hemolysin (alphaHL) from Staphylococcus aureus were assessed between pH 5.0 and 7.5 by measuring intrinsic tryptophan fluorescence, circular dichroism and elution time in size exclusion chromatography during urea denaturation. Decreasing the pH from 7.0 to 5.0 reduced the calculated DeltaG(u)(buff) from 8.9 to 4.2 kcal mol(-1), which correlates with an increased rate of pore formation previously observed over the same pH range. It is proposed that the lowered surface pH of biological membranes reduces the stability of alphaHL thereby modulating the rate of pore formation. Study holds ProTherm entries: 15016, 15017, 15018, 15019, 15020, 15021, 15022, 15023 Extra Details: alpha-hemolysin; stability transition

Submission Details

ID: fjvDnx2z3

Submitter: Connie Wang

Submission Date: April 24, 2018, 8:45 p.m.

Version: 1

Publication Details
Bortoleto RK;Ward RJ,FEBS Lett. (1999) A stability transition at mildly acidic pH in the alpha-hemolysin (alpha-toxin) from Staphylococcus aureus. PMID:10526180
Additional Information

Study Summary

Number of data points 24
Proteins Alpha-hemolysin ; Alpha-hemolysin
Unique complexes 1
Assays/Quantities/Protocols Experimental Assay: Cm buffers:sodium phosphate: 20 mM, pH:7.0 ; Experimental Assay: m buffers:sodium phosphate: 20 mM, pH:7.0 ; Experimental Assay: dG_H2O buffers:sodium phosphate: 20 mM, pH:7.0 ; Experimental Assay: Cm pH:5.0, buffers:acetate: 20 mM ; Experimental Assay: m pH:5.0, buffers:acetate: 20 mM ; Experimental Assay: dG_H2O pH:5.0, buffers:acetate: 20 mM ; Experimental Assay: Cm pH:7.5, buffers:sodium phosphate: 20 mM ; Experimental Assay: m pH:7.5, buffers:sodium phosphate: 20 mM ; Experimental Assay: dG_H2O pH:7.5, buffers:sodium phosphate: 20 mM ; Experimental Assay: Cm buffers:sodium phosphate: 20 mM, pH:7.0 ; Experimental Assay: m buffers:sodium phosphate: 20 mM, pH:7.0 ; Experimental Assay: dG_H2O buffers:sodium phosphate: 20 mM, pH:7.0 ; Experimental Assay: Cm buffers:sodium phosphate: 20 mM, pH:6.5 ; Experimental Assay: m buffers:sodium phosphate: 20 mM, pH:6.5 ; Experimental Assay: dG_H2O buffers:sodium phosphate: 20 mM, pH:6.5 ; Experimental Assay: Cm pH:6.0, buffers:sodium phosphate: 20 mM ; Experimental Assay: m pH:6.0, buffers:sodium phosphate: 20 mM ; Experimental Assay: dG_H2O pH:6.0, buffers:sodium phosphate: 20 mM ; Experimental Assay: Cm pH:5.5, buffers:acetate: 20 mM ; Experimental Assay: m pH:5.5, buffers:acetate: 20 mM ; Experimental Assay: dG_H2O pH:5.5, buffers:acetate: 20 mM ; Experimental Assay: Cm pH:5.0, buffers:acetate: 20 mM ; Experimental Assay: m pH:5.0, buffers:acetate: 20 mM ; Experimental Assay: dG_H2O pH:5.0, buffers:acetate: 20 mM
Libraries Mutations for sequence ADSDINIKTGTTDIGSNTTVKTGDLVTYDKENGMHKKVFYSFIDDKNHNKKLLVIRTKGTIAGQYRVYSEEGANKSGLAWPSAFKVQLQLPDNEVAQISDYYPRNSIDTKEYMSTLTYGFNGNVTGDDTGKIGGLIGANVSIGHTLKYVQPDFKTILESPTDKKVGWKVIFNNMVNQNWGPYDRDSWNPVYGNQLFMKTRNGSMKAADNFLDPNKASSLLSSGFSPDFATVITMDRKASKQQTNIDVIYERVRDDYQLHWTSTNWKGTNTKDKWTDRSSERYKIDWEKEEMTN

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
7AHL 1998-01-14 1.89 ALPHA-HEMOLYSIN FROM STAPHYLOCOCCUS AUREUS
3M4D 2010-05-05 1.9 Crystal structure of the M113N mutant of alpha-hemolysin
3M2L 2010-05-12 2.1 Crystal structure of the M113F mutant of alpha-hemolysin
3M3R 2010-05-05 2.2 Crystal structure of the M113F alpha-hemolysin mutant complexed with beta-cyclodextrin
3M4E 2010-05-05 2.3 Crystal structure of the M113N mutant of alpha-hemolysin bound to beta-cyclodextrin
4U6V 2014-09-17 2.56 Mechanisms of Neutralization of a Human Anti-Alpha Toxin Antibody
4YHD 2015-10-21 2.8 Staphylococcal alpha-hemolysin H35A mutant monomer
4IDJ 2013-06-26 3.36 S.Aureus a-hemolysin monomer in complex with Fab

Relevant UniProtKB Entries

Percent Identity Matching Chains Protein Accession Entry Name
99.7 Alpha-hemolysin Q2G1X0 HLA_STAA8
100.0 Alpha-hemolysin P09616 HLA_STAAU