tag:blogger.com,1999:blog-9633767.post186575455556433956..comments2024-03-25T09:11:17.877-07:00Comments on The Curious Wavefunction: How a college student can derive the RNA world hypothesis from scratchWavefunctionhttp://www.blogger.com/profile/14993805391653267639noreply@blogger.comBlogger6125tag:blogger.com,1999:blog-9633767.post-5195695759892422002011-03-30T18:33:23.948-07:002011-03-30T18:33:23.948-07:00one comment here is that only the terminal ribose ...one comment here is that only the terminal ribose has two open OH groups. So if you assume that the catalytic center is inside the molecule there would only be one OH group (as shown in your figure)<br /><br />for DNA the whole strand has only two OH groups (on either end)<br />incidentally I just posted something about that<br />http://chemical-quantum-images.blogspot.com/2011/03/dna-close-up.html<br /><br />but anyway it is a very good point that I have not thought of: the OH groups of RNA give its catalytical activityFelixhttps://www.blogger.com/profile/05138335803929997277noreply@blogger.comtag:blogger.com,1999:blog-9633767.post-82558785215992831132011-03-29T19:08:13.089-07:002011-03-29T19:08:13.089-07:00Those are all good points. The half-lives of phosp...Those are all good points. The half-lives of phosphate esters are short indeed (if by 4 years you mean short) but the esters could have been protected in primitive cell membranes (for instance look at Szostak's work) or they could have been concentrated in tidal pools. Naturally, we don't know the details. I am thinking that RNA catalysis probably co-evolved with assistance by some short peptides (whose half-lives are greater). The possibilities are myriad. As for our erstwhile student, if I understand the point correctly, she would already know about the relatively stability of mRNA and tRNA.Wavefunctionhttps://www.blogger.com/profile/14993805391653267639noreply@blogger.comtag:blogger.com,1999:blog-9633767.post-72666230514884986742011-03-28T22:31:52.207-07:002011-03-28T22:31:52.207-07:00I may be missing something, but a RNA world is sup...I may be missing something, but a RNA world is supposedly entirely populated of RNA species, with informative, replicative and "structural" properties, right? How then would the abovementioned student have resolved the issue with RNA stability as a limitation to a role for RNA as the information carrier?<br />As a way of introducing the concept, though, I think yours is fine :)<br />If we think of it, however, most cool ideas are probably perceived as such because they make a lot of "intuitive sense"....think of Darwinian evolution!<br />ciaofilipponoreply@blogger.comtag:blogger.com,1999:blog-9633767.post-43440829222627499802011-03-28T10:15:38.661-07:002011-03-28T10:15:38.661-07:00Thank you for an interesting post, but a question ...Thank you for an interesting post, but a question about the general notion of an RNA world: Does not the (uncatalyzed) hydrolytic half-life of the ester link at 25oC of just under 4 years (Wolfenden and Snider, 2001) present a challenge to the accumulation of RNA in the prebiotic oceans to significant levels? Might not the sources of significant quantities of ribose and phosphate in the oceans to overcome the thermochemical favoring of the hydrolytic products also seem to be an issue?<br /><br />Regards, D Ross/Palo AltoAnonymousnoreply@blogger.comtag:blogger.com,1999:blog-9633767.post-38447793153132979672011-03-27T19:40:35.744-07:002011-03-27T19:40:35.744-07:00Thanks. I don't know about others, but this ch...Thanks. I don't know about others, but this chain of reasoning really makes the RNA world sound logical and natural to me.Wavefunctionhttps://www.blogger.com/profile/14993805391653267639noreply@blogger.comtag:blogger.com,1999:blog-9633767.post-70121116065355019982011-03-27T12:56:53.534-07:002011-03-27T12:56:53.534-07:00An excellent and well-reasoned post!
When people ...An excellent and well-reasoned post!<br /><br />When people ask me why RNA is important (being that I work in an RNA lab) I will point them here!Anonymoushttps://www.blogger.com/profile/00549559153059700099noreply@blogger.com