Dear Gihan I would say collecting X-FEL data to solve a novel structure is unusual, as the real power of these machines is in time resolved experiments. If you have not already, I would recommend recording a fairly complete low dose data set on a synchrotron beamline with one or two of the crystals (I assume you must have thousands) to get the correct crystal parameters and do any molecular replacement. From there you would be in a much stronger position to analyse the X-FEL data and you will also have a useful reference data set to avoid indexing ambiguities etc.
Finally, if you are involved in an X-FEL experiment it is normal to have people on the proposal who are experienced with data processing - for X-FEL data this is not trivial - so you may find it is worth asking around in the lab / collaboration as well... Best wishes Graeme -----Original Message----- From: CCP4 bulletin board <CCP4BB@JISCMAIL.AC.UK> On Behalf Of Gihan Ketawala Sent: 19 April 2018 02:13 To: ccp4bb <ccp4bb@jiscmail.ac.uk> Subject: [ccp4bb] determining the point group and the space group Hi, my question is; how should one determine a point group and the space group of an unknown crystal? I have a protein crystal with know unit-cell parameters. (these are XFEL data so indexing wouldn't give the point and space groups). I checked the PDB, but no luck the PDB structures have the different space group assigned, no definitive answer hopefully, somebody can point me in the right direction Best, Gihan -- This e-mail and any attachments may contain confidential, copyright and or privileged material, and are for the use of the intended addressee only. If you are not the intended addressee or an authorised recipient of the addressee please notify us of receipt by returning the e-mail and do not use, copy, retain, distribute or disclose the information in or attached to the e-mail. Any opinions expressed within this e-mail are those of the individual and not necessarily of Diamond Light Source Ltd. Diamond Light Source Ltd. cannot guarantee that this e-mail or any attachments are free from viruses and we cannot accept liability for any damage which you may sustain as a result of software viruses which may be transmitted in or with the message. Diamond Light Source Limited (company no. 4375679). Registered in England and Wales with its registered office at Diamond House, Harwell Science and Innovation Campus, Didcot, Oxfordshire, OX11 0DE, United Kingdom
