[ccp4bb] 3rd Joint AIC-SILS Conference - 25-28 June 2018 Rome

[Giorgio Giardina]

Dear All,

We are pleased to announce that in 2018, from June 25 to June 28, the third 
joint conference of the Italian Crystallographic Association (AIC) and of the 
Italian Synchrotron Radiation Society (SILS) will be held in Rome. 

The program selected by the Scientific Committee will encourage the 
participation and contacts between members of the two associations involved, 
enabling ideas exchange in scientific fields concerning the study of condensed 
matter properties, such as Crystal Growth, Nanoscience, Methods and Techniques 
for the determination of Atomic, Electronic and Vibrational Structures, 
Molecular Recognition, Polymer and Materials Science, Molecular Medicine and 
Structural Biology. 

More information available at the following links:

http://www.cristallografia.org/congresso2018/
http://www.cristallografia.org/uploaded/4230.pdf

[ccp4bb] pseudo-centering or twinning problem in P3

[Giorgio Giardina]

Hello everybody,

I think I have a pseudo-centering problem.

I have a 1.6 ang. dataset of a mutant  protein that is an homodimer in solution.
Data processing gives the following SG:

Space group: P 31 2 1
Average unit cell:  111.36  111.36   28.56   90.00   90.00  120.00 
Average mosaicity:   0.24
Rmerge Overall 0.07

However with this SG the unit Cell is too small and monomer doesn't fit the in 
the AU.

I reprocessed the data in other possible SG (including P6) and finally I got 2 
equivalent SG's in which I can get a correct Molecular Replacement solution:

Space group: I 1 2 1 
Average unit cell:   57.07  111.11  192.90   90.00   90.07   90.00 

and

Space group: C 1 2 1
Average unit cell:  201.10  111.11   57.07   90.00  106.42   90.00 

Both with Average mosaicity:   0.38 and Rmerge Overall 0.06,
but the corresponding MR solutions do not refine, with R-factor stuck to 45-47%.

From what I understand, in the I121 SG I have the NC two-fold axis of the dimer 
at 1/2a and this originates the pseudo centering and the small P3 Cell

Largest Patterson peak with length larger than 15 Angstrom:
 Frac. coord.  :0.5000.0000.000
 Distance to origin:   28.566
 Height relative to origin :   53.830 %

I'm really not so good with symmetry, so I'll be grateful for any 
suggestion/help/solution from you out there.
Many thanks,
Giorgio

Re: [ccp4bb] Large Conformational Change Upon Binding Ligand...

[Giorgio Giardina]

Hi Jacob,

This is a paper on a large conformational change upon PLP binding.

http://www.ncbi.nlm.nih.gov/pubmed/22143761

Re: [ccp4bb] Collecting small-molecule diffraction on a Macromolecular xtallography beam line

[Giorgio Giardina]

You have been all wonderfully helpful.
The landscape is crystal-clear now.
Thanks to everybody.

Giorgio

[ccp4bb] Collecting small-molecule diffraction on a Macromolecular xtallography beam line

[Giorgio Giardina]

Hello,
I have some interesting small molecule xtals.
I was wondering if it is possible to collect a small molecule data-set using a 
sincrotron macromolecular  xtallography beam line, maybe with a very low beam 
intensity and moving the detector as close as possible?
Has anybody experienced that?
And if I get the images back home,  can I process them using standard 
macromolecular software or do I need ab-initio special programs?
Will MR work for phasing?

Thanks in advance,
Giorgio