Refmac with TLS terminates early when occupancy changed

From: Krisztian Fodor
Date: 20 December 2011 13:56

 Hello Guys,

I am trying to refine a 3.2 A complex structure with Refmac using TLS. It seems that I need to decrease the occupancy for a 38 amino acid peptide in the structure. However, after changing the occupancy to 0.50, Refmac terminates after 4 rounds of TLS refinement.

The only "error message" I can see is this towards the end of the log file:
Problem
 xyz         6480  -1.4325285     -0.92473793  etc.

And then it says that it is writing out coordinate files etc. which is obviously not happening, because the run was terminated too early.

Is this a bug? Any suggestions?

Thanks a lot,
Krisztian


--
Krisztian Fodor, PhD

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From: Debreczeni, Judit 

Hi Krisztian,

I have seen refmac fall over in a similar situation (low-ish res,
partially floppy model) during TLS refinement. You could try to rescue
it by
- using fixed TLS parameters from a previous (successful) refinement
- setting initial B-values to a fixed value
- including the peptide in one of the larger TLS groups (whichever
chain/domain it happens to be bound to)

JED.