Genome complexity: ribosome mechanics (Introduction)

by David Turell @, Sunday, June 30, 2013, 00:46 (3925 days ago) @ David Turell

A subunit rotates and a protein is made part by part from decoding the DNA bases presented by the messenger RNA:-"Translocation involves two steps (as Noller's lab showed back in 1989). Step one is the movement of the tRNA's "acceptor end" (where it carried the amino acid). This leads to a hybrid state, with the two ends of the tRNA in two different sites on the ribosome: the "anticodon end" is still lined up with the matching mRNA codon in one site, while the acceptor end has moved on to the next site. Step two is the movement of the tRNA's anticodon end together with the messenger RNA, which advances by one codon. Step two requires a catalyst called elongation factor G (EF-G). The new study shows the ribosome in the middle of step two, with EF-G bound to it and the tRNA halfway between the hybrid state and the final state.-"This is one of the most fundamental movements in all of biology, at the root of the whole mechanism for translation of the genetic code, and we now understand it all the way down to the molecular level," Noller said. "This mechanism had to be in place around the origin of life as we know it."-http://www.sciencedaily.com/releases/2013/06/130627142400.htm-
My bold. Think of the implications. This was present with the first fully developed cells.


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