Additive effects of a two-amino-acid insertion and a single-amino-acid substitution in dihydropteroate synthase for the development of sulphonamide-resistant Neisseria meningitidis
- 1 May 2000
- journal article
- research article
- Published by Microbiology Society in Microbiology
- Vol. 146 (5), 1151-1156
- https://doi.org/10.1099/00221287-146-5-1151
Abstract
Sulphonamide resistance in some clinical isolates of Neisseria meningitidis is associated with an insertion in the chromosomal folP gene leading to the addition of two amino acids, serine and glycine, in the drug target enzyme dihydropteroate synthase (DHPS). Removal of the insertion resulted in a markedly higher K m for the substrate p-aminobenzoic acid and a markedly lower K m for 2-amino-4-hydroxy-6-(hydroxymethyl)-7,8-dihydropteridine pyrophosphate. In the same isolates an additional important difference, compared to wild-type enzymes, was found at amino acid position 68, which is a proline in most DHPS enzymes, but is serine in one and leucine in another clinical isolate of sulphonamide-resistant N. meningitidis. The alteration at position 68 was found to affect mainly the level of sulphonamide resistance and had only a minor effect on the K m for the substrates. Introduction of the serine-glycine dipeptide at position 194 and a proline to serine substitution at position 68 in DHPS from normal, susceptible N. meningitidis failed to produce a functional sulphonamide-resistant enzyme. The conclusion of this study is that it is not possibile to change a normal chromosomally encoded DHPS of N. meningitidis to a sulphonamide-resistant one simply by an insertion of serine and glycine as seen in clinical isolates. It is likely that the resistance gene found in clinical isolates has evolved in another bacterial species where a combination of other amino acid changes may have contributed to produce a functionally resistant enzyme. This new resistance gene may have then been introduced into N. meningitidis by natural transformation.Keywords
This publication has 24 references indexed in Scilit:
- Virulence of antibiotic-resistant Salmonella typhimuriumProceedings of the National Academy of Sciences, 1998
- Crystal structure of the anti-bacterial sulfonamide drug target dihydropteroate synthaseNature Structural & Molecular Biology, 1997
- Structure and function of the dihydropteroate synthase from staphylococcus aureusJournal of Molecular Biology, 1997
- Adaptation to sulfonamide resistance in Neisseria meningitidis may have required compensatory changes to retain enzyme function: kinetic analysis of dihydropteroate synthases from N. meningitidis expressed in a knockout mutant of Escherichia coliJournal of Bacteriology, 1997
- Sulfonamide resistance in Neisseria meningitidis as defined by site-directed mutagenesis could have its origin in other speciesJournal of Bacteriology, 1995
- Trimethoprim and sulfonamide resistanceAntimicrobial Agents and Chemotherapy, 1995
- Sequence Variation of the Hydroxymethyldihydropterin Pyrophosphokinase: Dihydropteroate Synthase Gene in Lines of the Human Malaria Parasite, Plasmodium falciparum, with Differing Resistance to SulfadoxineEuropean Journal of Biochemistry, 1994
- Cloning, sequencing, and enhanced expression of the dihydropteroate synthase gene of Escherichia coli MC4100Journal of Bacteriology, 1992
- High efficiency transformation of E.coli by high voltage electroporationNucleic Acids Research, 1988
- STUDIES ON LYSOGENESIS IJournal of Bacteriology, 1951