Disease relevance of gyrB

• Accumulation of mutations in both gyrB and parE genes is associated with high-level resistance to novobiocin in Staphylococcus aureus [1].
• Streptococcus pneumoniae gyrA and gyrB genes specifying the DNA gyrase subunits have been cloned into pET plasmid vectors under the control of an inducible T7 promoter and have been separately expressed in Escherichia coli [2].

High impact information on gyrB

• These findings demonstrate that DNA gyrase is the primary target and that topoisomerase IV is the secondary target for novobiocin and that the accumulation of point mutations in both the gyrB and the parE genes is associated with high-level resistance to novobiocin in S. aureus [1].
• Species identification was confirmed by standard biochemical tests and analysis of 16S ribosomal DNA, gyrA, and gyrB sequences; all of the results were consistent with the S. aureus identification [3].
• Second-step mutants selected with NSFQ-105 had gyrA(S84L) alterations; those obtained with sparfloxacin carried a gyrA(D83A) mutation or a novel gyrB deletion (DeltaRKSAL, residues 405 to 409) affecting a trypsin-sensitive region linking functional domains of S. aureus GyrB [4].
• These results indicate that mutations in both gyrA and gyrB can be responsible for quinolone resistance in S. aureus [5].
• No mutants had any changes in grlB, and only one had a mutation in gyrB giving rise to the novel substitution Asp-437-->His [6].

Biological context of gyrB

• An expression plasmid was constructed by inserting the cloned genes into the Escherichia coli-S. aureus shuttle vector pAT19, and deletion plasmids carrying only functional gyrA and gyrB genes were derived from this plasmid [5].
• This fast and simple protocol, applied to pure culture strains, was developed using the gyrB DNA sequence, as previously proposed by other authors [7].

Other interactions of gyrB

• Portions of the gyrA (codons 60 to 120) and the gyrB (codons 420 to 480) genes of each clinical isolate were amplified by PCR and sequenced [8].
• Only two gyrB mutants and one grlB mutant were observed among the isolates: all contained a previously unreported mutation [9].
• No mutations were observed in either the gyrB or norA genes [10].

References