Hi Jacob, The size for the monomer of protein is 18 kd, and it forms a trimer. But in the current model, the monomer becomes two fragment. The missing connection part happens to be a loop containing a very short helix (8-10 residues) and one disulfide bond as deduced from its homologue crystal structure. We did run the gel for the crystal, but it looks same. Fengyun 引用 Jacob Keller ：

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Hi Fengyun,

How have you determined whether you in fact have the full-length protein in your crystals? It sounds like, from your statistics, that everything is already modelled--it seems hard to believe that 80% of the whole protein would give such good R values. Do others agree?

You could run some of your crystals on a gel next to a sample which is known to be full-length, and you could get the answer.

Jacob

******************************************* Jacob Pearson Keller Northwestern University Medical Scientist Training Program Dallos Laboratory F. Searle 1-240 2240 Campus Drive Evanston IL 60208 lab: 847.491.2438 cel: 773.608.9185 email: [email protected] *******************************************

----- Original Message ----- From: To: Sent: Tuesday, June 15, 2010 5:59 PM Subject: [phenixbb] is derivative data useful for looking for the missingpart of the model?

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Hi everyone,

I got a partial model, consisting of 80% of the whole molecule, from the molecular replacement. The native data reflects to 2.3 A, and now the R/Rfree= 0.22/0.28. My problem is that the missing part of the model is important for us, but there is not any density for this region now.

Meantime, we have several heavy atom derivative data. My question is that if refine the model against the derivative data, will the heavy atom appear in the difference map if existing? Any suggestions on how to use the derivative data to locate the missing part of model?

Thanks in advance! Regards, Fengyun

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