I had a structure that was done with crystals that were about a year
old. Initial crystals appeared in a less then a day and diffracted
very poorly. In trying to make room for more trays I reexamined the
old trays before throwing them out and low and behold nice well
diffracting crystals. Of course these are probably more the exception
then the rule.
Len
Leonard Thomas Ph. D.
Macromolecular Crystallography Laboratory Manager
University of Oklahoma
Department of Chemistry and Biochemistry
620 Parrington Oval
Norman, OK 73032
[log in to unmask]
Office: 405-325-1126
Lab: 405-325-7571
On Feb 5, 2009, at 2:05 PM, Nathaniel Echols wrote:
> Here's another very similar case:
>
> http://www.ncbi.nlm.nih.gov/pubmed/12270703
>
> On Thu, Feb 5, 2009 at 11:48 AM, William G. Scott <[log in to unmask]
> > wrote:
> Some things improve with age. Here is one of my favorite stories:
>
>
>
> http://tinyurl.com/oldtrna
>
>
> The crystal structure of yeast phenylalanine tRNA at 2.0 Å
> resolution: cleavage by Mg2+ in 15-year old crystals
>
> Luca Jovine, Snezana Djordjevica and Daniela Rhodes
>
> We have re-determined the crystal structure of yeast tRNAPhe to 2.0
> Å resolution using 15 year old crystals. The accuracy of the new
> structure, due both to higher resolution data and formerly
> unavailable refinement methods, consolidates the previous structural
> information, but also reveals novel details. In particular, the
> water structure around the tightly bound Mg2+ is now clearly
> resolved, and hence provides more accurate information on the
> geometry of the magnesium-binding sites and the role of water
> molecules in coordinating the metal ions to the tRNA. We have
> assigned a total of ten magnesium ions and identified a partly
> conserved geometry for high-affinity Mg2+ binding. In the electron
> density map there is also clear density for a spermine molecule
> binding in the major groove of the TΨC arm and also contacting a
> symmetry-related tRNA molecule. Interestingly, we have also found
> that two specific regions of the tRNA in the crystals are partially
> cleaved. The sites of hydrolysis are within the D and anticodon
> loops in the vicinity of Mg2+.
>
>
>
>
>
>
>
>
> On Feb 5, 2009, at 11:11 AM, Edward Snell wrote:
>
> </lurk_mode_off>
> </dumb_question_on>
>
> Dear All,
>
> I was recently trying to find references on how age may degrade a
> crystal, i.e. grow them and use them or preserve them as fresh as
> possible. I seem to remember seeing a couple of papers on this but my
> memory is fading and I have been unable to locate them. Can anyone jog
> my memory or tell me if I'm imagining things? I've found plenty on
> the
> protein prep etc. but nothing on the crystal.
>
> Thanks,
>
> Eddie.
>
>
> Edward Snell Ph.D.
> Assistant Prof. Department of Structural Biology, SUNY Buffalo,
> Hauptman-Woodward Medical Research Institute
> 700 Ellicott Street, Buffalo, NY 14203-1102
> Phone: (716) 898 8631 Fax: (716) 898 8660
> Email: [log in to unmask] Telepathy: 42.2 GHz
>
> Heisenberg was probably here! Crystallization, how quaint!
>
> </dumb_question_off>
> </lurk_mode_on>
>
|