s initiation and causes misreading of mRNA
s (bacteria). Very effective against Mycobacterium tuberculosis
, the "bug" causing tuberculosis
, but also used in veterinary medicine and against plant infections.
Streptomycin is produced by Streptomyces griseus
and contains three groups: N-methyl
, a methyl pentose
and an inositol
derivative with two guanidyl
residues (therefore I'm not even trying to draw it here).
interferes with the binding of formylmethionyl-tRNA to ribosome
s, therefore the mRNA that arrives at the ribosomes with the intention to be translated
into a protein
never occurs. But if it gets that far for the translation to start, misreading occurs because the streptomycin causes isoleucine
AUU) to be build in too, when only a phenylalanine
(UUU) is ment to go into the polypeptide
chain, resulting in a "wrong" protein.
Well, this for the good old days of sensitivity
to antibiotics. Because initially only several bacteria were resistant
to streptomycin, it was fairly easy to find out the trick of the resistant bacteria. It appeared to be just one point mutation
, the so-called 30S
subunit of the ribosome
. Even more precisely: the protein S12 is the key to sensitivity. Transfer of the resistance between bacteria occurs via the R-plasmid