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/* Copyright (C) 2001, 2002 Damir Zucic */
/*=============================================================================
set_chi1.c
Purpose:
Set the chi1 angle for each selected residue in the given complex.
A residue is treated as selected if the first atom of this residue
is selected. For proteins, this is typically the N atom (nitrogen).
Input:
(1) Pointer to MolComplexS structure.
(2) Pointer to ConfigS structure.
(3) The chi1 angle in degrees.
Output:
(1) Chi1 set for each selected residue in each caught complex.
(2) Return value.
Return value:
(1) Positive always (trivial).
Notes:
(1) This function ignores ALA, GLY and PRO.
========includes:============================================================*/
#include <stdio.h>
#include <string.h>
#include <X11/Xlib.h>
#include <X11/Xutil.h>
#include <X11/Xos.h>
#include <X11/Xatom.h>
#include "defines.h"
#include "typedefs.h"
/*======function prototypes:=================================================*/
int IsStandard_ (char *);
double Chi1FromNCACBCG_ (AtomS *, size_t, size_t);
double Chi1FromNCACBSG_ (AtomS *, size_t, size_t);
double Chi1FromNCACBCG1_ (AtomS *, size_t, size_t);
double Chi1FromNCACBOG_ (AtomS *, size_t, size_t);
double Chi1FromNCACBOG1_ (AtomS *, size_t, size_t);
int ExtractCACB_ (VectorS *, VectorS *, AtomS *, size_t, size_t);
int RotateAtom_ (AtomS *, VectorS *, VectorS *, double);
int DihedralAngles_ (MolComplexS *, ConfigS *);
/*======set chi1:============================================================*/
int SetChi1_ (MolComplexS *mol_complexSP, ConfigS *configSP, double chi1_new)
{
int residuesN, residueI;
size_t atomsN, atomI;
ResidueS *current_residueSP;
AtomS *first_atomSP;
char *residue_nameP;
size_t current_startI, current_endI;
int residue_typeI;
double chi1_old, delta_chi1;
int n;
static VectorS CA_vectorS, CB_vectorS;
AtomS *atomSP;
char *atom_nameP;
/* Copy the number of residues in the specified complex: */
residuesN = mol_complexSP->residuesN;
/* Copy the number of atoms in the specified complex: */
atomsN = mol_complexSP->atomsN;
/* Scan the residues: */
for (residueI = 0; residueI < residuesN; residueI++)
{
/* Pointer to the current residue: */
current_residueSP = mol_complexSP->residueSP + residueI;
/* Pointer to the first atom of this residue: */
first_atomSP = mol_complexSP->atomSP +
current_residueSP->residue_startI;
/* If the first atom of this residue is not */
/* selected, the residue is not selected: */
if (first_atomSP->selectedF == 0) continue;
/* The name of the current residue: */
residue_nameP = first_atomSP->raw_atomS.pure_residue_nameA;
/* The range of atomic indices for the current residue: */
current_startI = current_residueSP->residue_startI;
current_endI = current_residueSP->residue_endI;
/* Check is the current residue from */
/* the set of 20 standard residues: */
residue_typeI = IsStandard_ (residue_nameP);
/* Do nothing for ALA, GLY and PRO: */
if ((residue_typeI == 0) || (residue_typeI == 7) ||
(residue_typeI == 14)) continue;
/* Now calculate and check the old chi1 value. */
/* Initialize the old chi1: */
chi1_old = BADDIHEDANGLE;
/* Calculate the chi1_old: */
switch (residue_typeI)
{
/* Use N, CA, CB and CG for ARG, ASN, ASP, GLN, */
/* GLU, HIS, LEU, LYS, MET, PHE, TRP and TYR: */
case 1: /* ARG */
case 2: /* ASN */
case 3: /* ASP */
case 5: /* GLN */
case 6: /* GLU */
case 8: /* HIS */
case 10: /* LEU */
case 11: /* LYS */
case 12: /* MET */
case 13: /* PHE */
case 17: /* TRP */
case 18: /* TYR */
chi1_old = Chi1FromNCACBCG_ (mol_complexSP->atomSP,
current_startI,
current_endI);
break;
/* Use N, CA, CB and SG for CYS: */
case 4: /* CYS */
chi1_old = Chi1FromNCACBSG_ (mol_complexSP->atomSP,
current_startI,
current_endI);
break;
/* Use N, CA, CB and CG1 for ILE and VAL: */
case 9: /* ILE */
case 19: /* VAL */
chi1_old = Chi1FromNCACBCG1_ (mol_complexSP->atomSP,
current_startI,
current_endI);
break;
/* Use N, CA, CB and OG for SER: */
case 15: /* SER */
chi1_old = Chi1FromNCACBOG_ (mol_complexSP->atomSP,
current_startI,
current_endI);
break;
/* Use N, CA, CB and OG1 for THR: */
case 16: /* THR */
chi1_old = Chi1FromNCACBOG1_ (mol_complexSP->atomSP,
current_startI,
current_endI);
break;
/* At present, exotic residues are ignored: */
default:
;
}
/* Check the value: */
if (chi1_old == BADDIHEDANGLE) continue;
/* Calculate the difference: */
delta_chi1 = chi1_new - chi1_old;
/* Extract CA and CB coordinates: */
n = ExtractCACB_ (&CA_vectorS, &CB_vectorS,
mol_complexSP->atomSP, current_startI, current_endI);
if (n < 2) continue;
/* Change the chi1 angle: */
for (atomI = current_startI; atomI <= current_endI; atomI++)
{
/* Pointer to the current atom: */
atomSP = mol_complexSP->atomSP + atomI;
/* Pointer to the purified atom name: */
atom_nameP = atomSP->raw_atomS.pure_atom_nameA;
/* Do not rotate H, N, CA, HA, C, O and CB: */
if (strcmp (atom_nameP, "H" ) == 0) continue;
if (strcmp (atom_nameP, "N" ) == 0) continue;
if (strcmp (atom_nameP, "CA") == 0) continue;
if (strcmp (atom_nameP, "HA") == 0) continue;
if (strcmp (atom_nameP, "C" ) == 0) continue;
if (strcmp (atom_nameP, "O" ) == 0) continue;
if (strcmp (atom_nameP, "CB") == 0) continue;
/* Rotate the current atom about CA-CB bond: */
RotateAtom_ (atomSP, &CA_vectorS, &CB_vectorS, delta_chi1);
}
}
/* Update dihedral angles and cis-trans flags: */
DihedralAngles_ (mol_complexSP, configSP);
/* Set the position_changedF: */
mol_complexSP->position_changedF = 1;
/* Return positive value (trivial): */
return 1;
}
/*===========================================================================*/
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