If aa's joined to the first tRNA at an acceptor stem (with 3 bases?) at one side of its side chain -
then wouldn't that set up L - amino acids as the only ones that work?
Steps summary
:
AA joined to proto tRNA at acceptor stem with hydrogen bonds to 3 bases at acceptor stem end
At same time hydrogen bonds bind 3 bases at codon/anticodon
Both 'ends' denature at the same time in this molecule - and any other like minded ones in
prebiotic soup.
Thus certain groups of AA's (with similar side chains with similar bonding structures) are connected
with similar h bonds from antic/c
Thus when a certain group of AA's is released, their antic/c is separated too. This would be
symbiotic chemistry and could lead to the coding we know today.
We have two major classes of AA's - those that release at low hydrogen bonds and those that release
at high. (I would guess low would be phobic, high would be philic)
Also there are a number of middle h bonds that would allow for many variants.
Closer maybe?
Tom