Saturday, October 15, 2005

What's a Ribosome?

A Ribosome is an enzyme.In most books it's describe as a huge machinery that has a specific function o mapping mRNA into proteins and many creationists use this complicated design (much like a turing machine) as a proof of existence of a "designer".

However if we think it out differently we can see a ribosome as an enzyme that has no specificity (see previous article on enzymes and specificity) and whose function is to create peptidic bonds. This enzyme however has two mobile parts, the first one is a domain that allows for a "mobile specificity" that is provided by RNA molecules that can be of 4 types as well as a two other domains that allow for the entry of tRNAs and also peptides (the growing chain of protein).

The ribosome then catalyzes the reactions where there's a match between the "mobile specificity" and the tRNA anticodon, when this happens the aminoacid bonded to the tRNA is transferred to the poly-peptide chain and a conformational change causes the mRNA chain to be displaced and a new codon is presented to the ribosome.

This complex behavior could be simplified as an enzyme that could only catalyze peptide bond reaction formations and then allowed for some degree of specificity that later became more complex as codons were inserted as well as the mechanism of using a mRNA string that would lead to the catalyzing reaction to become irreversible.

A good way to prove this theory would be to prove that a ribosome would have catalytic capabilities even if it had only one of its parts (the top part with the tRNA input for instance) and this could be simulated using 3-D lattice grids.


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