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Mutations affecting the Rossman fold of isoleucyl-tRNA synthetase are correlated with low-level mupirocin resistance in Staphylococcus aureus.

ABSTRACT: The isoleucyl-tRNA synthetase (ileS) gene was sequenced in toto from 9 and in part from 31 Staphylococcus aureus strains with various degrees of susceptibility to mupirocin. All strains for which the mupirocin MIC was greater than 8 microg/ml contained point mutations affecting the Rossman fold via Val-to-Phe changes at either residue 588 (V588F) or residue 631 (V631F). The importance of the V588F mutation was confirmed by an allele-specific PCR survey of 32 additional strains. Additional mutations of uncertain significance were found in residues clustered on the surface of the IleS protein.

SUBMITTER: Antonio M

PROVIDER: S-EPMC127053 | biostudies-literature | 2002 Feb

REPOSITORIES: biostudies-literature

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Mutations affecting the Rossman fold of isoleucyl-tRNA synthetase are correlated with low-level mupirocin resistance in Staphylococcus aureus.

Antonio Martin M McFerran Neil N Pallen Mark J MJ

Antimicrobial agents and chemotherapy 20020201 2

The isoleucyl-tRNA synthetase (ileS) gene was sequenced in toto from 9 and in part from 31 Staphylococcus aureus strains with various degrees of susceptibility to mupirocin. All strains for which the mupirocin MIC was greater than 8 microg/ml contained point mutations affecting the Rossman fold via Val-to-Phe changes at either residue 588 (V588F) or residue 631 (V631F). The importance of the V588F mutation was confirmed by an allele-specific PCR survey of 32 additional strains. Additional mutati ...[more]

PMID: 11796355

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Isoleucyl-tRNA synthetase mutations in Staphylococcus aureus clinical isolates and in vitro selection of low-level mupirocin-resistant strains.

Project description: Not available

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Molecular analysis of isoleucyl-tRNA synthetase mutations in clinical isolates of methicillin-resistant Staphylococcus aureus with low-level mupirocin resistance.

Project description:Emergence and spread of low-level mupirocin resistance in staphylococci have been increasingly reported in recent years. The aim of this study was to characterize missense mutations within the chromosomal isoleucyl-tRNA synthetase gene (ileS) among clinical isolates of methicillin-resistant Staphylococcus aureus (MRSA) with low-level mupirocin resistance. A total of 20 isolates of MRSA with low-level mupirocin resistance (minimal inhibitory concentration, 16-64 microg/mL) were collected from 79 patients in intensive care units for six months. The isolates were analyzed for isoleucyl-tRNA synthetase (IleS) mutations that might affect the binding of mupirocin to the three-dimensional structure of the S. aureus IleS enzyme. All isolates with low-level mupirocin resistance contained the known V588F mutation affecting the Rossman fold, and some of them additionally had previously unidentified mutations such as P187F, K226T, F227L, Q612H, or V767D. Interestingly, Q612H was a novel mutation that was involved in stabilizing the conformation of the catalytic loop containing the KMSKS motif. In conclusion, this study confirms that molecular heterogeneity in ileS gene is common among clinical MRSA isolates with low-level mupirocin resistance, and further study on clinical mutants is needed to understand the structural basis of low-level mupirocin resistance.

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The catalytic flexibility of tRNAIle-lysidine synthetase can generate alternative tRNA substrates for isoleucyl-tRNA synthetase.

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Isoleucyl-tRNA synthetase interactome analysis

Project description:Aminoacyl-tRNA synthetases (aaRSs) catalyze the ligation of each amino acid to the 3’ hydroxyl group of the cognate tRNA and thereby establish the genetic code for protein synthesis. AaRSs form a complicated network through assembly into a multi-synthetase complex (MSC), which is comprised of nine aaRSs (ArgRS, AspRS, GlnRS, GluProRS, IleRS, LeuRS, LysRS, and MetRS) and three auxiliary proteins (aaRS-interacting multifunctional proteins, p43, p38, and p18 or AIMP1, 2, and 3) in vertebrates. IleRS is one of the least characterized aaRSs in the MSC. It is a class 1a aaRS and has an UNE-I domain at its C-terminal end that is formed by tandem ~90 residue repeats. Systematic depletion and yeast two-hybrid (Y2H) analyses suggest that IleRS binds to the WHEP domain of GluProRS through its UNE-I domain. However, crosslinking and mass spectrometry (XL-MS) analyses revealed that IleRS interacts with ArgRS, LeuRS, and MetRS in the MSC. While such difference may be due to the different dynamic states of the MSC under various cellular environments, it remains to be resolved how IleRS associates with other components of the MSC. Therefore, we performed mass spectrometry analysis to study IleRS interactome using cells expressing wild-type IleRS, C-terminal-deleted IleRS, and the IleRS UNE-I domain alone.

2023-03-11 | PXD031261 | Pride

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