[gmx-developers] Assignment of HISA and HISB in hizzie.c?

[Michael Shirts]

I'm working with the hizzie.c code, and it seems to me that it's not
working correctly in the assignment of a given HIS residue to HIS A or
HIS B.  Have other people had this problem?  I'm discovering that in
the code:

	  bHDd = chk_hbonds(nd1,pdba,x,acceptor,hbond,xh1,angle,dist);
	  chk_hbonds(nd1,pdba,x,donor,hbond,xh1,angle,dist);
	  bHEd = chk_hbonds(ne2,pdba,x,acceptor,hbond,xh2,angle,dist);
	  chk_hbonds(ne2,pdba,x,donor,hbond,xh2,angle,dist);
	  
	  if (bHDd) {
	    if (bHEd)
	      type = ehisH;
	    else 
	      type = ehisA;	  }
	  else 
	    type = ehisB;
	  fprintf(stderr,"Will use %s for residue %d\n",hh[type],hisnr+1);

If I put through a PDB file with a HD1 on ND1 (i.e. it should assign
ehisA), I get bHDd=bHEd=0, which defaults to ehisB.

First, this should give an error, (it's assuming that if bHDd =0, then
bHDe=1), which is not the case.  That, I can fix.  Secondly, it should
set  bHDd=1 if HD1 is bonded to ND1.  After looking through
chk_hbonds, I can't quite figure out how to fix this :).

Thanks,
Michael