>I would think that if the dimer was not repairable
>it would cause coding problems.
>
 I very much doubt that a dimer that forms on the anti-codon of a tRNA
would cause any problems in translation at all. The reason is that the
ribosome is just going to always reject it. Any and every tRNA is
rejected about 40-50 times for each time it is accepted and used by
the ribosome. So the only consequence would be a very minimal slowing
in the rate of translation but no effect on the protein produced, no
mistranslation.

TH
That makes sense. But let's take this back to the origin.
Then we have a real advantage to those proto-tRNAs
that don't have dimer damage in the anti-codon (or proto anti-codon). So that
suggests real coding limitations in those proto anti-codons that are not
rejected.
doesn't it? And in turn it suggests limitations on whatever the tRNA is
reading.

WH
 The consequences of a dimer on a mRNA would be a different matter.
There may be some mistranslation in this case. But tRNAs have long
lifetimes and are repeatably reused, while mRNAs have only lifetimes
of a few minutes in bacteria and maybe something over an hour in
eukaryotes. There just isn't much time for dimer damage to occur on
the mRNA.
 William L Hunt

TH
Again, back to the origin. I wonder if instead of having
a clear cut mRNA and a tRNA it wouldn't be more likely to have two proto tRNA's
or two folded RNA strands  which may give some stability to the one acting the
mRNA part.

Perhaps the proto mRNA is  folded/annealed in cold, and denatured and read in
hot.

Whether that's true or not, there would probably be a huge onslaught of UV I
would think.

I can't see that the absorbency of UV in RNA is a coincidence.

>
>
> Or how do you think it would effect the
>translation today? Or does it even matter how dimers effect
>translation today in discussing OOL or origins of the code?
> In a similiar vein, how does a dimer on the mRNA effect translation
>TODAY? Or how do you think it would effect the translation of the mRNA
>today?
>
>  William L Hunt
> >>
>
>
> >>



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