The penC mutation conferring antibiotic resistance in Neisseria gonorrhoeae arises from a mutation in the PilQ secretin that interferes with multimer stability
Open Access
- 25 July 2005
- journal article
- Published by Wiley in Molecular Microbiology
- Vol. 57 (5), 1238-1251
- https://doi.org/10.1111/j.1365-2958.2005.04752.x
Abstract
The penC resistance gene was previously characterized in an FA19 penA mtrR penB gonococcal strain (PR100) as a spontaneous mutation that increased resistance to penicillin and tetracycline. We show here that antibiotic resistance mediated by penC is the result of a Glu‐666 to Lys missense mutation in the pilQ gene that interferes with the formation of the SDS‐resistant high‐molecular‐mass PilQ secretin complex, disrupts piliation and decreases transformation frequency by 50‐fold. Deletion of pilQ in PR100 confers the same level of antibiotic resistance as the penC mutation, but increased resistance was observed only in strains containing the mtrR and penB resistance determinants. Site‐saturation mutagenesis of Glu‐666 revealed that only acidic or amidated amino acids at this position preserved PilQ function. Consistent with early studies suggesting the importance of cysteine residues for stability of the PilQ multimer, mutation of either of the two cysteine residues in FA19 PilQ led to a similar phenotype as penC: increased antibiotic resistance, loss of piliation, intermediate levels of transformation competence and absence of SDS‐resistant PilQ oligomers. These data show that a functional secretin complex can enhance the entry of antibiotics into the cell and suggest that the PilQ oligomer forms a pore in the outer membrane through which antibiotics diffuse into the periplasm.Keywords
This publication has 63 references indexed in Scilit:
- Low-Level Pilin Expression Allows for Substantial DNA Transformation Competence in Neisseria gonorrhoeaeInfection and Immunity, 2003
- Three-Dimensional Structure of the Neisseria meningitidis Secretin PilQ Determined from Negative-Stain Transmission Electron MicroscopyJournal of Bacteriology, 2003
- Overexpression of the MtrC-MtrD-MtrE Efflux Pump Due to an mtrR Mutation Is Required for Chromosomally Mediated Penicillin Resistance in Neisseria gonorrhoeaeJournal of Bacteriology, 2002
- Analysis of the PilQ Secretin from Neisseria meningitidis by Transmission Electron Microscopy Reveals a Dodecameric Quaternary StructureJournal of Bacteriology, 2001
- Modulation of Gonococcal Piliation by Regulatable Transcription of pilEJournal of Bacteriology, 2001
- Mutants at conserved positions in gene IV, a gene required for assembly and secretion of filamentous phagesMolecular Microbiology, 1994
- Site-directed mutagenesis by overlap extension using the polymerase chain reactionGene, 1989
- Penicillin‐binding protein 2 genes of non‐β‐lactamase‐producing, penicillin‐resistant strains of Neisseria gonorrhoeaeMolecular Microbiology, 1989
- THE GENETICS OF THE GONOCOCCUSAnnual Review of Microbiology, 1984
- The Surface Properties of Neisseria gonorrhoeae: Isolation of the Major Components of the Outer MembraneJournal of General Microbiology, 1977