Use of single-cysteine mutants to probe the location of the disulfide bond in LamB protein from Escherichia coli.
The two cysteine residues of the LamB protein of Escherichia coli outer membrane have been shown to form an intrasubunit disulfide whose location differs greatly in the two current topology models of the LamB protein. This study probes the location of the disulfide by examining conditions for intersubunit disulfide formation in single-cysteine mutants of LamB protein. Formation of an intersubunit bond in the purified mutant proteins, which resulted in a disulfide-linked dimer, only occurred after heat treatment, suggesting the disulfide is not exposed on the surface in the native protein.
Ling
R
R
Department of Chemistry and Biochemistry, San Francisco State University, CA 94132.
Luckey
M
M
D001425:Bacterial Outer Membrane Proteins; D003545:Cysteine; D004220:Disulfides; D004926:Escherichia coli / Q000737:chemistry; D016297:Mutagenesis, Site-Directed; D010446:Peptide Fragments / Q000737:chemistry; D018272:Porins; D011991:Receptors, Virus / Q000737:chemistry*; D013329:Structure-Activity Relationship
D001425:Bacterial Outer Membrane Proteins; D004220:Disulfides; D010446:Peptide Fragments; D018272:Porins; D011991:Receptors, Virus; C016532:maltoporins; D003545:Cysteine