Dear developers,<br>
<br>
I need to compute the PMF for rotating an angle (in particular, the
angle between two atoms in a small molecule and a reference atom in a
protein), and I've been trying to do this using the existing angle
restraints code, but it isn't working well for me since angle
restraints (unlike distance and dihedral restraints) currently use a
functional form that involves a cosine rather than simple harmonic
angle restraints. This means that the force has more than one zero and
sometimes the angle I'm restraining can end up trapped at the alternate
zero of the force (the one OPPOSITE the one I'm restraining to). <br>
<br>
Anyway, I wanted to inquire whether any of the developers would be
interested in adding an alternate angle restraint type, perhaps type
"2", which would use simple harmonic restraints (like, for example, the
dihedral restraints), as I can imagine this would be useful to others,
and should be relatively straightforward. I am willing to help test it.<br>
<br>
Alternatively, I suppose, I can just implement it in my own code. Or I
can do so and when I get it working I can share with others. But it
seemed like it might make more sense to have it put into GROMACS
itself, as I can't imagine I'm the only one who ever wants to have
simple harmonic angle restraints.<br>
<br>
Thanks,<br>
David<br>
<br>