Streptomycin-resistance of Euglena gracilis chloroplasts: identification of a point mutation in the 16S rRNA gene in an invariant position.

AUTOR(ES)

Montandon, P E

RESUMO

We sequenced the chloroplast 16S rRNA gene of two Euglena gracilis mutants which contain streptomycin-resistant chloroplasts (Smr 139.12/4 and Smr 139.20/2). These mutants are known to contain a single intact rrn operon per circular chloroplast genome. Nucleotide sequence comparison between a 16S rRNA gene of wild type Euglena gracilis, strain Z, with streptomycin-sensitive chloroplasts, and the 16S rRNA gene of both Smr-strains reveals a single base change (C to T) at position 876. This position is equivalent to the invariant position 912 of the E. coli 16S rRNA gene. The analogous position is also conserved in all chloroplast small subunit RNA genes from lower and higher plants sequenced so far. Light dependent protein synthesis with purified chloroplasts from streptomycin-resistant cells is not inhibited by streptomycin. Based on the results reported here we postulate linkage between the observed point mutation on the 16S rRNA gene and streptomycin-resistance of chloroplast 70S ribosomes.

Documentos Relacionados

• Mechanisms of Streptomycin Resistance: Selection of Mutations in the 16S rRNA Gene Conferring Resistance
• Nucleotide sequence of a Euglena gracilis chloroplast gene coding for the 16S rRNA: homologies to E. coli and Zea mays chloroplast 16S rRNA.
• 16S rRNA Mutation-Mediated Tetracycline Resistance in Helicobacter pylori
• Novel mutation in 16S rRNA associated with streptomycin dependence in Mycobacterium tuberculosis.
• A new mutation in 16S rRNA of Escherichia coli conferring spectinomycin resistance.