TY - JOUR
T1 - Assembly-defective OmpC mutants of Escherichia coli K-12
AU - Xiong, Xiaoling
AU - Deeter, Jack N.
AU - Misra, Rajeev
PY - 1996/2
Y1 - 1996/2
N2 - Novel ompC(Dex) alleles were utilized to isolate mutants defective in OmpC biogenesis. These ompC(Dex) alleles also conferred sensitivity to sodium dodecyl sulfate (SDS), which permitted the isolation of SDS-resistant and OmpC-specific phage-resistant mutants that remained Dex+. Many mutants acquired resistance against these lethal agents by lowering the OmpC level present in the outer membrane. In the majority of these mutants, a defect in the assembly (metastable to stable trimer formation) was responsible for lowering OmpC levels. The assembly defects in various mutant OmpC proteins were caused by single-amino-acid substitutions involving the G-39, G-42, G- 223, G-224, Q-240, G-251, and G-282 residues of the mature protein. This assembly defect was correctable by an assembly suppressor allele, asmA3. In addition, we investigated one novel OmpC mutant in which an assembly defect was caused by a disulfide bond formation between two nonnative cysteine residues. The assembly defect was fully corrected in a genetic background in which the cell's ability to form disulfide bonds was compromised. The assembly defect of the two-cysteine OmpC protein was also mended by asmA3, whose suppressive effect was not achieved by preventing disulfide bond formation in the mutant OmpC protein.
AB - Novel ompC(Dex) alleles were utilized to isolate mutants defective in OmpC biogenesis. These ompC(Dex) alleles also conferred sensitivity to sodium dodecyl sulfate (SDS), which permitted the isolation of SDS-resistant and OmpC-specific phage-resistant mutants that remained Dex+. Many mutants acquired resistance against these lethal agents by lowering the OmpC level present in the outer membrane. In the majority of these mutants, a defect in the assembly (metastable to stable trimer formation) was responsible for lowering OmpC levels. The assembly defects in various mutant OmpC proteins were caused by single-amino-acid substitutions involving the G-39, G-42, G- 223, G-224, Q-240, G-251, and G-282 residues of the mature protein. This assembly defect was correctable by an assembly suppressor allele, asmA3. In addition, we investigated one novel OmpC mutant in which an assembly defect was caused by a disulfide bond formation between two nonnative cysteine residues. The assembly defect was fully corrected in a genetic background in which the cell's ability to form disulfide bonds was compromised. The assembly defect of the two-cysteine OmpC protein was also mended by asmA3, whose suppressive effect was not achieved by preventing disulfide bond formation in the mutant OmpC protein.
UR - http://www.scopus.com/inward/record.url?scp=0030043116&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0030043116&partnerID=8YFLogxK
U2 - 10.1128/jb.178.4.1213-1215.1996
DO - 10.1128/jb.178.4.1213-1215.1996
M3 - Article
C2 - 8576061
AN - SCOPUS:0030043116
SN - 0021-9193
VL - 178
SP - 1213
EP - 1215
JO - Journal of bacteriology
JF - Journal of bacteriology
IS - 4
ER -