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Re: [ccp4bb] practical limits of MR? |
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CCP4bb navigationCCP4bb <-- 2007 <-- March 2007 <-- 05 March 2007Subject: Re: practical limits of MR? From: Nat Echols echols {- at -} UCLINK {- dot -} BERKELEY {- dot -} EDU Date: 2007-03-05 > structure, so all options are open, right? They don't have to be elegant, > it just has to work. :) Yes, but it's not worth wasting time and resources on something that is guaranteed to fail. In this case, it's a 50kD protein that doesn't have any homologues in the PDB (the best match is ~25% over maybe 70 residues), and PHYRE generates a model that probably approximates the topology reasonably well but doesn't have a very good e-value and certainly doesn't resemble the sequence of the original model. This is far worse than any successful solution I've heard of, and given the number of times a 100% identical model doesn't provide a solution, I'm not inclined to waste my time on theoretical models or PDB-wide searches. In this case, "desperation" means the crystals are nearly impossible to reproduce, and only one data set was ever collected. (We could try phasing using every structure from E. coli or at least 25% identical to an E. coli protein, in case the crystals were of a contaminant. But if the protein was what we wanted, this won't work.) CCP4bb navigationCCP4bb <-- 2007 <-- March 2007 <-- 05 March 2007 |
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