4u26
Crystal structure of the E. coli ribosome bound to dalfopristin and quinupristin.Crystal structure of the E. coli ribosome bound to dalfopristin and quinupristin.
Structural highlights
FunctionRS5_ECOLI With S4 and S12 plays an important role in translational accuracy. Many suppressors of streptomycin-dependent mutants of protein S12 are found in this protein, some but not all of which decrease translational accuracy (ram, ribosomal ambiguity mutations).[1] Located at the back of the 30S subunit body where it stabilizes the conformation of the head with respect to the body.[2] The physical location of this protein suggests it may also play a role in mRNA unwinding by the ribosome, possibly by forming part of a processivity clamp.[3] Publication Abstract from PubMedStreptogramin antibiotics are divided into type A and B streptogramins, which in combination can act synergistically. We compared the molecular interactions of the streptogramin combinations Synercid (type A: dalfopristin, type B: quinupristin) and NXL 103 (type A: flopristin, type B: linopristin) with the Escherichia coli 70S ribosome by x-ray crystallography. We further analyzed the activity of the streptogramin components individually and in combination. Streptogramin A and B components in Synercid and NXL 103 exhibit synergistic antimicrobial activity against certain pathogenic bacteria. However, in transcription-coupled translation assays, only combinations that include dalfopristin, the streptogramin A component of Synercid, show synergy. Notably, the diethylaminoethylsulfonyl group in dalfopristin reduces its activity, but is the basis for synergy in transcription-coupled translation assays before its rapid hydrolysis from the depsipeptide core. Replacement of the diethylaminoethylsulfonyl group in dalfopristin by a non-hydrolyzable group may therefore be beneficial for synergy. The absence of general streptogramin synergy in transcription-coupled translation assays suggests that synergistic antimicrobial activity of streptogramins can occur independently of streptogramin effects on translation. Synergy of streptogramin antibiotics occurs independently of their effects on translation.,Noeske J, Huang J, Olivier NB, Giacobbe RA, Zambrowski M, Cate JH Antimicrob Agents Chemother. 2014 Jun 23. pii: AAC.03389-14. PMID:24957822[4] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
|
|