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/* Copyright (C) 2001-2003 Damir Zucic */
/*=============================================================================
set_omega.c
Purpose:
Set the omega 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 omega angle in degrees.
Output:
(1) Omega angle set for each selected residue in each caught complex.
(2) Return value.
Return value:
(1) Positive always (trivial).
Notes:
(1) This function uses the atoms N and CA of the current residue and
and the atoms CA and C of the previous residue.
========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 ExtractNCA_ (VectorS *, VectorS *, AtomS *, size_t, size_t);
int ExtractCAC_ (VectorS *, VectorS *, AtomS *, size_t, size_t);
double OmegaFromCACNCA_ (VectorS *, VectorS *, VectorS *, VectorS *,
ConfigS *);
int RotateAtom_ (AtomS *, VectorS *, VectorS *, double);
int DihedralAngles_ (MolComplexS *, ConfigS *);
/*======set omega angle(s):==================================================*/
int SetOmega_ (MolComplexS *mol_complexSP, ConfigS *configSP, double omega_new)
{
int residuesN, residueI;
size_t atomsN, atomI;
ResidueS *current_residueSP;
AtomS *first_atomSP;
size_t current_startI, current_endI;
int n;
static VectorS N_vectorS, CA_vectorS;
ResidueS *previous_residueSP;
size_t previous_startI, previous_endI;
static VectorS previousCA_vectorS, previousC_vectorS;
double omega_old, delta_omega;
AtomS *atomSP;
/* 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 residues, but skip the first one: */
for (residueI = 1; 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 range of atomic indices for the current residue: */
current_startI = current_residueSP->residue_startI;
current_endI = current_residueSP->residue_endI;
/* Try to extract N and CA coordinates for the current residue: */
n = ExtractNCA_ (&N_vectorS, &CA_vectorS,
mol_complexSP->atomSP, current_startI, current_endI);
if (n < 2) continue;
/* The CA and C atoms of the previous residue are required. */
/* Pointer to the previous residue: */
previous_residueSP = mol_complexSP->residueSP + residueI - 1;
/* The atomic index range for the previous residue: */
previous_startI = previous_residueSP->residue_startI;
previous_endI = previous_residueSP->residue_endI;
/* Extract CA and C coordinates from the previous residue: */
n = ExtractCAC_ (&previousCA_vectorS, &previousC_vectorS,
mol_complexSP->atomSP,
previous_startI, previous_endI);
if (n < 2) continue;
/* Calculate and check the old omega: */
omega_old = OmegaFromCACNCA_ (&previousCA_vectorS, &previousC_vectorS,
&N_vectorS, &CA_vectorS,
configSP);
if (omega_old == BADDIHEDANGLE) continue;
/* Calculate the difference: */
delta_omega = omega_new - omega_old;
/* Rotate all atoms of the current residue and all */
/* atoms after the current residue about C-N bond: */
for (atomI = current_startI; atomI < atomsN; atomI++)
{
/* Pointer to the current atom: */
atomSP = mol_complexSP->atomSP + atomI;
/* Rotate the current atom about N-CA bond: */
RotateAtom_ (atomSP,
&previousC_vectorS, &N_vectorS, delta_omega);
}
}
/* 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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