[AMBER] Backbone position restraints as a group

From: lorenaz <lorenaz.bii.a-star.edu.sg>
Date: Wed, 5 Dec 2018 16:49:57 +0800

Hi all,

I am working on a membrane protein that needs to have its transmembrane
backbones restrained at all times (in order to preserve the curvature of
the membrane). I suppose I could do this with

ntr=1, restraintmask=':396-495.CA,C,O,N | :963-1062.CA,C,O,N'

However, at the same time I need to heat and equilibrate the system,
which means that the entire protein + membrane needs to be heavily
restrained. Restraints are gradually removed during the NPT run (10 -->
5 --> 1 --> 0 kcal/(mol*A^2)). For this, I can create a restrained group:

Hold protein and membrane fixed
10.0                         ! Force constant (kcal/(mol A^2))
RES 1 2487            ! Choose residues to restrain
END
END

If I understand correctly, I cannot use group and restraintmask at the
same time. If that is true, how can I define protein TM region backbone
as a group?

Best,

Lorena






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Received on Wed Dec 05 2018 - 01:00:02 PST
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