Premium
Genetic mapping of starch‐ and Lambda‐receptor sites in maltoporin: identification of substitutions causing direct and indirect effects on binding sites by cysteine mutagenesis
Author(s) -
Francis G.,
Brennan L.,
Stretton S.,
Ferenci T.
Publication year - 1991
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/j.1365-2958.1991.tb02160.x
Subject(s) - biology , mutagenesis , site directed mutagenesis , cysteine , biochemistry , lambda phage , binding site , mutant , escherichia coli , mutation , microbiology and biotechnology , gene , bacteriophage , enzyme
Summary Cysteine mutagenesis was used to test the proximity of 16 residues to protein‐ligand interaction sites in maltoporin (LamB protein). LamB protein with additional cysteines was incorporated into the outer membrane of Escherichia coli except with a Ser‐30→ Cys substitution. Phage Lambda and starch binding was assayed before and after incubation of mutants with six thiol‐specific reagents. Four categories of mutation were recognized on the basis of phenotype and modification for each of the Lambda‐ and starch binding sites. The thiol modification experiments helped to clarify whether the phenotype of a mutation was due to a substitution at the binding site or an indirect perturbation of the structure. This study suggests that the cysteine mutagenesis/thiol modification approach may be usefully applied to the operational mapping of surface‐accessible binding sites or epitopes.