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50 lines
1.1 KiB
C

#include "stride.h"
int PlaceHydrogens(CHAIN *Chain)
{
int Res, i, N, C, CA, H, PlacedCnt=0;
float Length_N_C, Length_N_CA, Length_N_H;
RESIDUE *r, *rr;
for( Res=1; Res<Chain->NRes; Res++ ) {
r = Chain->Rsd[Res];
rr = Chain->Rsd[Res-1];
if( !strcmp(r->ResType,"PRO") ) continue;
/* Replace deiterium atoms by hydrogens */
if( FindAtom(Chain,Res,"D",&H) )
strcmp(r->AtomType[H],"H");
if( !FindAtom(Chain,Res,"H",&H) && FindAtom(Chain,Res,"N",&N) &&
FindAtom(Chain,Res-1,"C",&C) && FindAtom(Chain,Res,"CA",&CA) ) {
H = r->NAtom;
Length_N_C = Dist(r->Coord[N],rr->Coord[C]);
Length_N_CA = Dist(r->Coord[N],r->Coord[CA]);
for( i=0; i<3; i++ )
r->Coord[H][i] = r->Coord[N][i] -
( (rr->Coord[C][i] - r->Coord[N][i])/Length_N_C +
(r->Coord[CA][i] - r->Coord[N][i])/Length_N_CA );
Length_N_H = Dist(r->Coord[N],r->Coord[H]);
for( i=0; i<3; i++ )
r->Coord[H][i] = r->Coord[N][i] +
DIST_N_H*(r->Coord[H][i]-r->Coord[N][i])/Length_N_H;
strcpy(r->AtomType[H],"H");
r->NAtom++;
PlacedCnt++;
}
}
return(PlacedCnt);
}