"The Qb virus doesn't need anything as complicated as a cell in order to
>replicate: a test tube full of suitable chemicals is enough. The
>experiment, conducted by Sol Spiegelman of the University of Illinois,
>consisted of introducing the viral RNA into a medium containing the RNA's
>own replication enzyme, plus a supply of raw materials and some salts, and
>incubating the mixture.
This "monster" amounts to simply assaying an error prone enzyme. Yes, you
can select for better templates with this system, but you must have the
very complicated polymerase and nucleotide triphosphates, specific metals,
etc. The RNA world cannot rely on the protein polymerase.
> Even a single RNA molecule added to the broth was
>enough to trigger a population explosion. But then something truly amazing
>was discovered. Replicating strands of RNA were still produced even when
>not a single molecule of viral RNA was added! To return to my architectural
>analogy, it was rather like throwing a pile of bricks into a giant mixer
>and producing, if not a house, then at least a garage. At first Eigen found
>the results hard to believe, and checked to see whether accidental
>contamination had occurred.
I also find this very difficult to believe as quoted, ie that RNA was
produced without a template. To my knowledge, polymerases require templates
to start with. Otherwise RNA would be popping up all over the place.
Like
>scrapie and kuru, BSE is caused not by a bacterium or a virus, but by a
>fragment of protein that can replicate and spread. Might such fragments be
>surviving relics of a primitive life form based solely on proteins?"
The prion protein does not "replicate" except to interact with other prion
proteins to pass along its pathogenic conformation. It does not "replicate
and spread" like a virus. It only spreads through preexisting prion
proteins. This is completely different from short "self-replicating" peptides.
Bob Bateman
This archive was generated by hypermail 2b29 : Mon Jan 24 2000 - 10:49:32 EST