Sorry - I should have added that, yes, there are 2 identical peptide chains that should be parallel coiled-coil. Any advice gratefully received. Ed
-----Original Message----- From: cockburn [mailto:[EMAIL PROTECTED] Sent: Fri 3/28/2008 1:35 PM To: Thomas Edwards Subject: Re: [ccp4bb] MolRep of coiled coils Hi Thomas, Does your coiled-coil consist of two polypeptide chains, and are their sequences identical? Do you expect it to be a parallel or anti-parallel coiled-coil? Yours Joe Thomas Edwards a écrit : > Dear BB, > > I am attempting molecular replacement with a 2.8A data set from crystals of a > coiled coil of about 150 residues. > Probably p21212 but maybe p2221. > > So far, Phaser, MolRep, Amore, Mr Bump, have not provided a good solution as > judged by Z-scores, CCs, Rfactors, and whether there is any density outside > the model (there should be - I'm using a slightly shorter model to search > with). > > One possible problem is that the coiled coil may not be straight. It may have > a slight curve to it. > I have used models from the PDB that are straight or slightly curved, so far > with no success. > I have tried a few different resolution cutoffs too. > I have tried single helix chains or dimeric coiled coils. > > Is there anything special about MR with coiled coils? > Can anybody provide any tips/hints on MR with coiled coils?? > > Thanks > Ed >
