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Short answer - CAN'T BE. If you dissolve crystals and run SDS PAGE and/or mass-spec and do not see the cleavage it means that there is an error in your electron density. Some disorder is really hard to model even having the atomic resolution data, and some main chain bonds might have much lower density than the others creating an appearance of cleavage. Petr On Thursday 01 December 2005 02:01 am, Jinkwang wrote: > Hi all, > Routine MR solution of a mutant structure was an easy task until I found a > clear cleavage within the polypeptide chain. This cleavage is reproducible > only in crystal structure, and biochemical studies such as SDS-PAGE, > N-terminal sequencing or Mass spectra never indicate any cleavage in the > chain. > > > > The protein has about 700 amino acids, divided into alpha (200 a.a) and > beta (500) chains. The cleavage is found at 28-29 of the beta chain in the > crystal. Wondering whether this could occur only in crystal states, the > crystals were dissolved, but the biochemical studies did not show any > cleavage, but crystal structure once again shows. > > > > Any comments are highly appreciated. > > > > Regards, > > Jin Kwang
