ISSN:
1617-4623
Keywords:
Biased mutation pressure
;
Deviated genetic code
;
Mycoplasma capriocolum
;
Tryptophan tRNAs
;
UGA codon
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Summary Mycoplasma capricolum uses two tryptophan codons, the “universal” nonsense condon UGA and the universal codon UGG. The bacterium contains two tryptophan tRNAs, one with anticodon UCA, (U: 2′-O-methyl U derivative), and the other with CCA (5′-C: partially 2′-O-methylated). tRNAUCA would translate codons UGA and probably UGG by wobbling. tRNACCA is much less charged by tryptophan in the cells than tRNAUCA, and the intracellular amount of tRNACCA is 5–10 times lower than that of tRNAUCA. The genes for these two tRNAs are separated by a terminator-like structure in a single operon. In vitro transcription experiments suggest that the predominance of tRNAUCA over tRNACCA results from the attenuation of transcription by this terminator-like structure.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00334708
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