4u27
From Proteopedia
Crystal structure of the E. coli ribosome bound to flopristin and linopristin.
Structural highlights
FunctionRS19_ECOLI In the E.coli 70S ribosome in the initiation state (PubMed:12809609) it has been modeled to contact the 23S rRNA of the 50S subunit forming part of bridge B1a; this bridge is broken in the model with bound EF-G. The 23S rRNA contact site in bridge B1a is modeled to differ in different ribosomal states (PubMed:12859903), contacting alternately S13 or S19. In the 3.5 angstroms resolved ribosome structures (PubMed:16272117) the contacts between L5, S13 and S19 bridge B1b are different, confirming the dynamic nature of this interaction. Bridge B1a is not visible in the crystallized ribosomes due to 23S rRNA disorder.[HAMAP-Rule:MF_00531] Protein S19 forms a complex with S13 that binds strongly to the 16S ribosomal RNA. Contacts the A site tRNA.[HAMAP-Rule:MF_00531] 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[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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