MECHANISM OF STREPTOMYCIN ACTION IN MYCOBACTERIUM TUBERCULOSIS H37Rv

Abstract

70S ribosomes isolated from a streptomycin (8m) sensitive strain of M. tuberculosis H37Rv bind labelled streptomycin rapidly. This binding depends on the drug concentration. At low concentration, there is one binding site on the ribosome, which increases to two as the concentration is increased. Sm causes a small amount of miscoding in a cell-free, poly U-directed system from M. tuberculosis H37Rv containing 8m-sensitive ribosomes. There are no differences in the uptake of 'H-dihydrostreptomycin (DH 8m) by whole cells of 8m-sensitive and resistant strains; the uptake decreases after 1 hour and again increases upto about 8 hours. 8m causes the slow release of fMet-tRNA, from a preformed initiation complex, in vitro.