TY - JOUR

T1 - Sites of interaction of streptogramin A and B antibiotics in the peptidyl transferase loop of 23 S rRNA and the synergism of their inhibitory mechanisms.

AU - Porse, B T

AU - Garrett, R A

N1 - Keywords: Bacillus megaterium; Bacterial Proteins; Binding Sites; Chloramphenicol; Drug Resistance, Microbial; Drug Synergism; Halobacterium salinarum; Macromolecular Substances; Models, Biological; Nucleic Acid Conformation; Peptide Chain Elongation, Translational; Peptidyl Transferases; Point Mutation; RNA, Ribosomal, 23S; Ribosomes; Virginiamycin

PY - 1999

Y1 - 1999

N2 - Streptogramin antibiotics contain two active A and B components that inhibit peptide elongation synergistically. Mutants resistant to the A component (virginiamycin M1 and pristinamycin IIA) were selected for the archaeon Halobacterium halobium. The mutations mapped to the universally conserved nucleotides A2059 and A2503 within the peptidyl transferase loop of 23 S rRNA (Escherichia coli numbering). When bound to wild-type and mutant haloarchaeal ribosomes, the A and B components (pristinamycins IIA and IA, respectively) produced partially overlapping rRNA footprints, involving six to eight nucleotides in the peptidyl transferase loop of 23 S rRNA, including the two mutated nucleotides. An rRNA footprinting study, performed both in vivo and in vitro, on the A and B components complexed to Bacillus megaterium ribosomes, indicated that similar drug-induced effects occur on free ribosomes and within the bacterial cells. It is inferred that position 2058 and the sites of mutation, A2059 and A2503, are involved in the synergistic inhibition by the two antibiotics. A structural model is presented which links A2059 and A2503 and provides a structural rationale for the rRNA footprints.

AB - Streptogramin antibiotics contain two active A and B components that inhibit peptide elongation synergistically. Mutants resistant to the A component (virginiamycin M1 and pristinamycin IIA) were selected for the archaeon Halobacterium halobium. The mutations mapped to the universally conserved nucleotides A2059 and A2503 within the peptidyl transferase loop of 23 S rRNA (Escherichia coli numbering). When bound to wild-type and mutant haloarchaeal ribosomes, the A and B components (pristinamycins IIA and IA, respectively) produced partially overlapping rRNA footprints, involving six to eight nucleotides in the peptidyl transferase loop of 23 S rRNA, including the two mutated nucleotides. An rRNA footprinting study, performed both in vivo and in vitro, on the A and B components complexed to Bacillus megaterium ribosomes, indicated that similar drug-induced effects occur on free ribosomes and within the bacterial cells. It is inferred that position 2058 and the sites of mutation, A2059 and A2503, are involved in the synergistic inhibition by the two antibiotics. A structural model is presented which links A2059 and A2503 and provides a structural rationale for the rRNA footprints.

U2 - 10.1006/jmbi.1998.2509

DO - 10.1006/jmbi.1998.2509

M3 - Journal article

C2 - 9973558

VL - 286

SP - 375

EP - 387

JO - Journal of Molecular Biology

JF - Journal of Molecular Biology

SN - 0022-2836

IS - 2

ER -