title: Stabilising and destabilising modifications of cysteines in the E. coli outer membrane porin protein OmpC.
abstract: Three sulfhydryl labels were used to modify two mutated sites, R37C and R74C in the eyelet of the outer membrane porin OmpC. Modification of R37C with the neutral groups Aldrithiol and bimane increases thermal stability but the negatively charged iodoacetate causes a decrease in thermal stability. The effects of substitution at R74C were less significant. Bimane labelling increases the voltage sensitivity and decreases the single channel conductance at R37C asymmetrically with smaller channels being recorded at cis negative voltages. Negatively charged acetate does not affect the voltage gating.
authors.affiliation: Department of Biochemistry and Genetics, The Medical School, University of Newcastle, Newcastle upon Tyne, UK.
authors.forename: I
authors.initials: I
authors.lastname: Gokce
authors.forename: G
authors.initials: G
authors.lastname: Bainbridge
authors.forename: J H
authors.initials: JH
authors.lastname: Lakey
mesh_terms: D001425:Bacterial Outer Membrane Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D001643:Bridged Bicyclo Compounds / Q000378:metabolism; D002942:Circular Dichroism; D003545:Cysteine / Q000737:chemistry* / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D004594:Electrophysiology; D004926:Escherichia coli / Q000737:chemistry*; D015640:Ion Channel Gating; D008958:Models, Molecular; D009154:Mutation; D018272:Porins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D011487:Protein Conformation; D011489:Protein Denaturation; D013050:Spectrometry, Fluorescence; D013439:Sulfhydryl Reagents / Q000494:pharmacology; D013696:Temperature
chemical_list: D001425:Bacterial Outer Membrane Proteins; D001643:Bridged Bicyclo Compounds; D018272:Porins; D013439:Sulfhydryl Reagents; D003545:Cysteine; C028381:monobromobimane