2 observations: 'collapsed' forms of calmodulin ligand also exist that indicate the 'function' of wrapping itself around a target.
Second, the real question is what the 'function' to be elucidated means - if it involves a binding site detail, resolution (i.e. coordinate precision) sure is 'biologically' relevant. In the case of Cam, a large domain movement as key part of the function will be subject to all the well known crystal packing caveats and may require multiple structures etc. I.e., to get the big picture, small detail is less relevant - as many valuable low resolution structures (open-closed channels, etc) demonstrate. BR -----Original Message----- From: CCP4 bulletin board [mailto:CCP4BB@JISCMAIL.AC.UK] On Behalf Of Jacob Keller Sent: Sunday, May 22, 2011 7:07 PM To: CCP4BB@JISCMAIL.AC.UK Subject: Re: [ccp4bb] Crystal structure and NMR structure I think calmodulin is a classic example, in all its forms (I believe that there are both NMR and crystal structures for all of these): +/- calcium, +/- peptide. Especially the no-peptide +/- calcium forms differ pretty substantially. The calcium-bound no-peptide structures are particularly interesting, as it seems that the NMR structure is much more plausible (take a look if you don't believe me--the xtal structure has a really extended alpha helix, which it seems to me would be bending all over the place in solution). And yet, the crystal structure was solved at 1.0 Ang. Now, assuming that the NMR structure is really a truer picture of the structure in solution, this contradicts a premise which always seemed reasonable to me, that as resolution increases, the model more accurately represents the protein as found in solution. I guess the bottom line is that resolution does not necessarily imply a better picture of the molecule as it functions physiologically, but simply means that the crystallography worked out better. Do others agree with this, that resolution implies little about the physiological veracity of the model? Jacob On Sat, May 21, 2011 at 4:03 AM, Chen Guttman <guttm...@bgu.ac.il> wrote: > Here you go: > http://www.ncbi.nlm.nih.gov/pubmed/12015150 > Domain swapping of Cyanovirin. > Chen > > --- > Chen Guttman > The Zarivach laboratory for Macromolecular Crystallography > Building 39, Room 009B > Ben-Gurion University of the Negev > POBox 653 > Zip Code 84105 > Beer-Sheva > Israel > http://lifeserv.bgu.ac.il/wb/zarivach > Tel. +972-8-6479519 > Fax. +972-8-6472970 > > > On Sat, May 21, 2011 at 08:34, Vandu Murugan <wandumuru...@gmail.com> wrote: >> >> Dear all, >> I would like to get some information on proteins where there is >> conformation/structural change between the crystal structure and solution >> structure of the same protein. Do anybody came across such situations? >> Thanks in advance.. >> >> cheers, >> Vandu > > -- ******************************************* Jacob Pearson Keller Northwestern University Medical Scientist Training Program cel: 773.608.9185 email: j-kell...@northwestern.edu *******************************************
