Dear Monica Given you have eliminated all other phasing possibilities I would try phasing from native atoms e.g. sulphur. If you have reasonable resolution and you can collect data at a long wavelength from many samples (which has been shown to improve the phasing signals under some circumstances) you may be able to get yourself phases or at least a decent amount of signal which could be combined with highly partial MR solutions to bootstrap your way.
There are also methods which allow phasing from highly incomplete MR models given good data ™ however your mileage may vary. There was a discussion on this subject on this very forum recently. Your problem here if your crystals do not diffract so well is “hard” so your cumbersome alternative could be necessary. However in the meantime effort in optimising the crystals you can obtain already is probably well spent. Best wishes Graeme From: CCP4 bulletin board [mailto:[email protected]] On Behalf Of Monica Mittal Sent: 05 October 2015 08:39 To: ccp4bb Subject: [ccp4bb] Advice for Structure Determination Dear all, I need a general advice. I don't have a suitable Model (Lets say only with a similarity of 15%) and no other model to solve the structure by MR. Then i think of anomalous experiments, but soaking with heavy metals is not good for the crystals. Since the protein is being expressed in Pichia cells, growth in Seleno-media is cumbersome. There are no ligands or ions that i can use for anomalous scattering of protein crystals. I am trying to express it in bacteria but have some issues. What is the option that i can choose to solve the structure of such a protein ? Your suggestions are highly recommended. Thanks in advance. Monica -- 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
