Streptovaricin- And Rifampigin-Resistange of Rna Polymerase in a Resistant Clone of Escherichia Coli B

Nitta, Kazuo; Mizuno, Satoshi; Yamazaki, Hisaji; Umezawa, Hamao

doi:10.7164/antibiotics.21.521

Cited by 19 publications

(4 citation statements)

References 5 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Shortly after RIF was shown to inhibit transcription, cell-free assays demonstrated that resistance, at least in laboratory strains, was related to a change in the properties of the polymerase: RNAP from resistant bacteria was itself resistant in these assays, and it did not bind RIF. [9][10][11][12] That the target within the enzyme was the b subunit, one of its two largest polypeptides, was first suggested by the observation that in a RIF r Escherichia coli strain the migration of this subunit in polyacrylamide gel electrophoresis was altered. 13 Subsequently, separation and mixed reconstitution of enzymatically active core enzyme, using subunits from susceptible and RIF r strains of E. coli 14 and Bacillus subtilis, 15 provided a more direct demonstration that resistance was determined by a change in the b subunit.…”

Section: Primary Mechanism Of Resistance To Rif: Mutations Affecting mentioning

confidence: 99%

Resistance to rifampicin: a review

Goldstein¹

2014

J Antibiot

322

236

View full text Add to dashboard Cite

Resistance to rifampicin (RIF) is a broad subject covering not just the mechanism of clinical resistance, nearly always due to a genetic change in the β subunit of bacterial RNA polymerase (RNAP), but also how studies of resistant polymerases have helped us understand the structure of the enzyme, the intricacies of the transcription process and its role in complex physiological pathways. This review can only scratch the surface of these phenomena. The identification, in strains of Escherichia coli, of the positions within β of the mutations determining resistance is discussed in some detail, as are mutations in organisms that are therapeutic targets of RIF, in particular Mycobacterium tuberculosis. Interestingly, changes in the same three codons of the consensus sequence occur repeatedly in unrelated RIF-resistant (RIF(r)) clinical isolates of several different bacterial species, and a single mutation predominates in mycobacteria. The utilization of our knowledge of these mutations to develop rapid screening tests for detecting resistance is briefly discussed. Cross-resistance among rifamycins has been a topic of controversy; current thinking is that there is no difference in the susceptibility of RNAP mutants to RIF, rifapentine and rifabutin. Also summarized are intrinsic RIF resistance and other resistance mechanisms.

show abstract

Section: Primary Mechanism Of Resistance To Rif: Mutations Affecting mentioning

confidence: 99%

Resistance to rifampicin: a review

Goldstein¹

2014

J Antibiot

322

236

View full text Add to dashboard Cite

show abstract

“…Streptovaricins (X, Figure 2) (38)(39)(40)(41) and tolypomycins belong to this group (42)(43)(44). Streptovaricins have antibiotic activities closely resembling those of rifamycins, they have the same mecha nism of action (45,46), and they show cross-resistance with rifamycins (47)(48)(49)(50). Some streptovaricins also exhibit an activity on poxviruses and on RNA-dcpendent DNA polymerase (51,52).…”

Section: Chemistrymentioning

confidence: 99%

Rifamycins: A General View

Riva¹,

Silvestri²

1972

Annu. Rev. Microbiol.

126

View full text Add to dashboard Cite

“…Both antibiotics inhibit DNA-directed RNA polymerase in bacterial cells more strongly than any other known agent.38 It seems likely that both antibiotics act at a similar site, since E. coli resistant to one of the antibiotics is also resistant to the other. 39 structural requirements needed to ensure activity have not been ascertained. In view of the wide variety of rifamycin derivatives which retain antibacterial activity, the principal requisite feature may be the ansa bridge.…”

Section: Biological Activitymentioning

confidence: 99%