descriptors.c File Reference

#include "../headers/descriptors.h"

Go to the source code of this file.

Functions
s_desc *	allocate_s_desc (void)
void	reset_desc (s_desc *desc)
void	set_descriptors (s_atm **atoms, int natoms, s_vvertice **tvert, int nvert, s_desc *desc, int niter, s_pdb *pdb, int flag_do_expensive_calculations)
int	get_vert_apolar_density (s_vvertice **tvert, int nvert, s_vvertice *vert)
int	countResidues (s_atm *atoms, int natoms, char chain[2])
void	set_atom_based_descriptors (s_atm **atoms, int natoms, s_desc *desc, s_atm *all_atoms, int all_natoms)
void	set_aa_desc (s_desc *desc, const char *aa_name)

---

Function Documentation

s_desc* allocate_s_desc

(

void

)

## FUNCTION: allocate_s_desc

## SPECIFICATION: Allocate a descroptor structure

## PARAMETRES:

## RETURN: s_desc*

Definition at line 86 of file descriptors.c.

References my_malloc(), and reset_desc().

Referenced by desc_pocket().

{
        s_desc *desc = (s_desc*)my_malloc(sizeof(s_desc)) ;
        
        reset_desc(desc) ;

        return desc ;
}

int countResidues	(	s_atm *	atoms,
		int	natoms,
		char	chain[2]
	)

Definition at line 333 of file descriptors.c.

References s_atm::chain, and s_atm::res_id.

Referenced by set_atom_based_descriptors().

                                                          {
    int i,
            n=0,
            curRes=-1,
            firstRes=-1,
            lastRes=-1;
    s_atm *curatom = NULL ;
    for(i=0;i<natoms;i++){
        curatom = &(atoms[i]) ;
        if(!strncmp(curatom->chain,chain,1) ){
            if(firstRes==-1) firstRes=curatom->res_id;
            lastRes=curatom->res_id;
            if(curRes!=curatom->res_id){
                curRes=curatom->res_id;
                n+=1;
            }
        }
    }
    return lastRes-firstRes;
}

int get_vert_apolar_density	(	s_vvertice **	tvert,
		int	nvert,
		s_vvertice *	vert
	)

## FUNCTION: get_vert_apolar_density

## SPECIFICATION: Here we calculate the number of apolar vertices (vertices that contact at least 3 atoms having their electronegativity > 2.7) that lie within a range of 0-r () from a given reference vertice, r being its own radius.

It provides the apolar density for a given vertice, that will be used for the calculation of the total apolar density of the pocket, defined as the mean value of it.

## PARAMETRES: @ s_vvertice **tvert : The list of vertices @ int nvert : The number of vertices @ s_vvertice *vert : The reference vertice.

## RETURN: int: The apolar density as defined previously.

Definition at line 309 of file descriptors.c.

References dist(), M_APOLAR_AS, s_vvertice::ray, s_vvertice::type, s_vvertice::x, s_vvertice::y, and s_vvertice::z.

{
        int apol_neighbours = 0,
                i = 0 ;

        s_vvertice *vc = NULL ;

        float vx = vert->x, 
                  vy = vert->y,
                  vz = vert->z,
                  vray = vert->ray ;
        
        for(i = 0 ; i < nvert ; i++) {
                vc = tvert[i] ;
                if(vc != vert && vc->type == M_APOLAR_AS){
                        if(dist(vx, vy, vz, vc->x, vc->y, vc->z)-(vc->ray + vray) <= 0.) {
                                apol_neighbours += 1 ;
                        }
                }
        }

        return apol_neighbours ;
}

void reset_desc

(

s_desc *

desc

)

## FUNCTION: reset_s_desc

## SPECIFICATION: Reset descriptors to 0 values.

## PARAMETRES:

## RETURN: void

Definition at line 108 of file descriptors.c.

References s_desc::aa_compo, s_desc::apolar_asphere_prop, s_desc::as_density, s_desc::as_density_norm, s_desc::as_max_dst, s_desc::as_max_dst_norm, s_desc::characterChain1, s_desc::characterChain2, s_desc::charge_score, s_desc::drug_score, s_desc::flex, s_desc::hydrophobicity_score, s_desc::masph_sacc, s_desc::mean_asph_ray, s_desc::mean_loc_hyd_dens, s_desc::mean_loc_hyd_dens_norm, s_desc::nas_norm, s_desc::nb_asph, s_desc::numResChain1, s_desc::numResChain2, s_desc::polarity_score, s_desc::polarity_score_norm, s_desc::prop_asapol_norm, s_desc::prop_polar_atm, s_desc::surf_apol_vdw, s_desc::surf_apol_vdw14, s_desc::surf_apol_vdw22, s_desc::surf_pol_vdw, s_desc::surf_pol_vdw14, s_desc::surf_pol_vdw22, s_desc::surf_vdw, s_desc::surf_vdw14, s_desc::surf_vdw22, s_desc::volume, and s_desc::volume_score.

Referenced by allocate_s_desc(), reset_pocket(), and set_pockets_descriptors().

{
    desc->hydrophobicity_score = 0.0 ;
    desc->volume_score = 0.0 ;
    desc->volume = 0.0 ;
    desc->prop_polar_atm = 0.0 ;
    desc->mean_asph_ray = 0.0 ;
    desc->masph_sacc = 0.0 ;
    desc->apolar_asphere_prop = 0.0 ;
    desc->mean_loc_hyd_dens = 0.0 ;
    desc->as_density = 0.0 ;
    desc->as_max_dst = 0.0 ;

    desc->flex = 0.0 ;
    desc->nas_norm = 0.0 ;
    desc->prop_asapol_norm = 0.0 ;
    desc->mean_loc_hyd_dens_norm = 0.0 ;
    desc->as_density_norm = 0.0 ;
    desc->polarity_score_norm = 0.0 ;
    desc->as_max_dst_norm = 0.0 ;

    desc->nb_asph = 0 ;
    desc->polarity_score  = 0 ;
    desc->charge_score = 0 ;

    desc->surf_apol_vdw=0.0;
    desc->surf_apol_vdw14=0.0;
    desc->surf_apol_vdw22=0.0;

    desc->surf_pol_vdw=0.0;
    desc->surf_pol_vdw14=0.0;
    desc->surf_pol_vdw22=0.0;

    desc->surf_vdw=0.0;
    desc->surf_vdw14=0.0;
    desc->surf_vdw22=0.0;

    desc->drug_score=0.0;
    desc->numResChain1=0;
    desc->numResChain2=0;
    desc->characterChain1=0;
    desc->characterChain2=0;

    int i ;
    for(i = 0 ; i < 20 ; i++) desc->aa_compo[i] = 0 ;
}

void set_aa_desc	(	s_desc *	desc,
		const char *	aa_name
	)

## FUNCTION: set_aa_desc

## SPECIFICATION: Set amino-acid based descriptors.

## PARAMETRES: @ s_desc *desc : OUTPUT: Structure of descriptors to fill @ const char *aa_name : The amino acid name

## RETURN: s_desc*

Definition at line 469 of file descriptors.c.

References s_desc::aa_compo, s_desc::charge_score, get_charge_from_idx(), get_hydrophobicity_score_from_idx(), get_polarity_from_idx(), get_volume_score_from_idx(), s_desc::hydrophobicity_score, M_ALA_IDX, M_ARG_IDX, M_ASN_IDX, M_ASP_IDX, M_CYS_IDX, M_GLN_IDX, M_GLU_IDX, M_GLY_IDX, M_HIS_IDX, M_ILE_IDX, M_LEU_IDX, M_LYS_IDX, M_MET_IDX, M_PHE_IDX, M_PRO_IDX, M_SER_IDX, M_THR_IDX, M_TRP_IDX, M_TYR_IDX, M_VAL_IDX, s_desc::polarity_score, and s_desc::volume_score.

Referenced by set_atom_based_descriptors().

{       
        int aa_idx = -1;
        char l1 = aa_name[0], 
                 l2 = aa_name[1], 
                 l3 = aa_name[2] ;

        /* Ok, lets use the less comparisons possible... (may be used in the aa.c
         * file later!) 
         * Only A, C, G, H, I, L, M, P, S, T and V possibility for the first letter:
         **/
        switch(l1) {
                case 'A' : /* Either ALA, ASP, ASN or ARG */
                        if(l2 == 'L') aa_idx = M_ALA_IDX ;                              /* ALA amino acid! */
                        else if(l2 == 'R') aa_idx = M_ARG_IDX ;                 /* ARG amino acid! */
                        else if(l2 == 'S' && l3 ==  'P') 
                                aa_idx = M_ASP_IDX ;                                            /* ASP amino acid! */
                        else aa_idx = M_ASN_IDX ; break ;                               /* ASN amino acid! */
                        
                case 'C' : aa_idx = M_CYS_IDX ; break ;                         /* CYS amino acid! */
                        
                case 'G' : /* Either GLU, GLY, or GLN, so just check the 3rd letter */
                        if(l3 == 'U') aa_idx = M_GLU_IDX ;                              /* GLU amino acid! */
                        else if(l3 == 'Y') aa_idx = M_GLY_IDX ;                 /* GLY amino acid! */
                        else aa_idx = M_GLN_IDX ; break ;                               /* GLN amino acid! */

                case 'H' : aa_idx = M_HIS_IDX ; break ;                         /* HIS amino acid! */
                case 'I' : aa_idx = M_ILE_IDX ; break ;                         /* ILE amino acid! */
                        
                case 'L' : /* Either ALA, ASP, ASN or ARG */
                        if(l2 == 'Y') aa_idx = M_LYS_IDX ;                              /* LYS amino acid! */
                        else aa_idx = M_LEU_IDX ; break ;                               /* LEU amino acid! */
                        
                case 'M' : aa_idx = M_MET_IDX ; break ;                         /* MET amino acid! */
                case 'P' : /* Either ALA, ASP, ASN or ARG */
                        if(l2 == 'H') aa_idx = M_PHE_IDX ;                              /* PHE amino acid! */
                        else aa_idx = M_PRO_IDX ; break ;                               /* PRO amino acid! */

                case 'S' : aa_idx = M_SER_IDX ; break ;                         /* SER amino acid! */

                case 'T' : /* Either ALA, ASP, ASN or ARG */
                        if(l2 == 'H') aa_idx = M_THR_IDX ;                              /* THR amino acid! */
                        else if(l2 == 'R') aa_idx = M_TRP_IDX ;                 /* TRP amino acid! */
                        else aa_idx = M_TYR_IDX ; break ;                               /* TYR amino acid! */

                case 'V' : aa_idx = M_VAL_IDX ; break ;                         /* VAL amino acid! */

                default: /*fprintf(stderr, "! Amno acid %s does not exists!\n", aa_name) ;*/
                        break ;
        }

        /* Ok now we have our amino acid, lets update statistics! */

        if(aa_idx != -1) {
                desc->aa_compo[aa_idx] ++ ;
                desc->hydrophobicity_score += get_hydrophobicity_score_from_idx(aa_idx) ;
                desc->polarity_score += get_polarity_from_idx(aa_idx) ;
                desc->volume_score += get_volume_score_from_idx(aa_idx) ;
                desc->charge_score += get_charge_from_idx(aa_idx) ;
        }
}

void set_atom_based_descriptors	(	s_atm **	atoms,
		int	natoms,
		s_desc *	desc,
		s_atm *	all_atoms,
		int	all_natoms
	)

## FUNCTION: set_atom_based_descriptors

## SPECIFICATION: Update atomic descriptors of the pocket for the given atom. Here, we just update mean bfactor, electronegativity, amino-acids scores...

## PARAMETRES: @ s_atom *atoms : The atoms @ int natoms : Number of atoms @ s_desc *desc : OUTPUT : The descriptor structure to fill

## RETURN: void

Definition at line 373 of file descriptors.c.

References s_atm::bfactor, s_atm::chain, s_desc::characterChain1, s_desc::characterChain2, countResidues(), s_atm::electroneg, element_in_kept_res(), element_in_nucl_acid(), element_in_std_res(), s_desc::flex, s_desc::hydrophobicity_score, in_tab(), s_desc::interChain, s_desc::nameChain1, s_desc::nameChain2, s_desc::numResChain1, s_desc::numResChain2, s_desc::prop_polar_atm, s_atm::res_id, s_atm::res_name, set_aa_desc(), and s_desc::volume_score.

Referenced by set_descriptors().

{
        s_atm *curatom = NULL ;
        s_atm *firstatom = NULL;
        int i,
                curChar = 0, 
                res_ids[natoms],        /* Maximum natoms residues contacting the pocket */
                nb_res_ids = 0 ;        /* Current number of residus */

        int nb_polar_atm = 0 ;
        char curChainName[2];
        if(atoms){
            firstatom=atoms[0];
            desc->interChain=0;

            if(element_in_std_res(firstatom->res_name))             desc->characterChain1=0;
            else if(element_in_nucl_acid(firstatom->res_name))      desc->characterChain1=1;
            else if(element_in_kept_res(firstatom->res_name))       desc->characterChain1=2;
            strcpy(desc->nameChain1,firstatom->chain);
            strcpy(curChainName,firstatom->chain);
            desc->numResChain1 = countResidues(all_atoms,all_natoms,firstatom->chain);

            for(i = 0 ; i < natoms ; i++) {
                    curatom = atoms[i] ;
                    if(curatom!=firstatom){
                        if(strcmp(curatom->chain,firstatom->chain)!=0 && desc->interChain < 1) {
                            desc->interChain = 1;
                            if(!desc->numResChain2){
                                desc->numResChain2 = countResidues(all_atoms,all_natoms,curatom->chain);
                                strncpy(curChainName,curatom->chain,1);
                            }
                        }

                        if(element_in_std_res(curatom->res_name)){
                            curChar=0;
                            //strcpy(curChainName,curatom->chain);
                        }
                        else if(element_in_nucl_acid(curatom->res_name)){
                            curChar=1;
                            //strcpy(curChainName,curatom->chain);
                        }
                        else if(element_in_kept_res(curatom->res_name)){
                            curChar=2;
                            //strcpy(curChainName,curatom->chain);
                        }
                        if(curChar!=desc->characterChain1){
                            desc->characterChain2=curChar;
                            //strcpy(curChainName,curatom->chain);
                        }
                    }
            /* Setting amino acid descriptor of the current atom */
                    if(in_tab(res_ids,  nb_res_ids, curatom->res_id) == 0) {
                            set_aa_desc(desc, atoms[i]->res_name) ;
                            res_ids[nb_res_ids] = curatom->res_id ;
                            nb_res_ids ++ ;
                    }

            /* Setting atom descriptor */
                    desc->flex += curatom->bfactor ;
                    if(curatom->electroneg > 2.7)  nb_polar_atm += 1 ;
            }

            if(!desc->numResChain2) desc->numResChain2 = countResidues(all_atoms,all_natoms,curatom->chain);
            strcpy(desc->nameChain2,curChainName);

            /*fprintf(stdout,":%s:",desc->ligTag);*/
            desc->hydrophobicity_score = desc->hydrophobicity_score/ (float) nb_res_ids ;
            desc->volume_score = desc->volume_score / (float) nb_res_ids ;

            desc->flex /= natoms ;
            desc->prop_polar_atm = ((float) nb_polar_atm) / ((float) natoms) * 100.0 ;
        }
        else {
            desc->hydrophobicity_score=0.0;
            desc->volume_score=0.0;
            desc->flex=0.0;
            desc->prop_polar_atm=0.0;
        }

}

void set_descriptors	(	s_atm **	atoms,
		int	natoms,
		s_vvertice **	tvert,
		int	nvert,
		s_desc *	desc,
		int	niter,
		s_pdb *	pdb,
		int	flag_do_expensive_calculations
	)

## FUNCTION: set_descriptors

## SPECIFICATION: Set descriptors using a set of atoms with corresponding voronoi vertices. Current descriptors (need to be improved...) includes atom/AA based descriptors and voronoi vertice based descriptors. A word on several descriptors:

• The "solvent accessibility" of a sphere (which is rather the buriedness degree...) is defined as the distance of the barycenter of the sphere (defined using the 4 contacted atoms) from the center of the sphere.
• The mean_loc_hyd_dens is the mean value of apolar density calculated for each vertice and defined in the next function (see comments or doc)

## PARAMETRES: @ s_atm **atoms : The list of atoms @ int natoms : The number of atoms @ s_vvertice **tvert : The list of vertices @ int nvert : The number of vertices @ s_desc *desc : OUTPUT: The descriptor structure to fill

## RETURN: void: s_desc is filled

Definition at line 182 of file descriptors.c.

References s_desc::apolar_asphere_prop, s_desc::as_density, s_desc::as_max_dst, s_desc::as_max_r, s_vvertice::bary, dist(), get_verts_volume_ptr(), s_pdb::latoms, M_APOLAR_AS, s_desc::masph_sacc, s_desc::mean_asph_ray, s_desc::mean_loc_hyd_dens, s_pdb::natoms, s_desc::nb_asph, s_vvertice::ray, set_ASA(), set_atom_based_descriptors(), s_vvertice::type, s_desc::volume, s_vvertice::x, s_vvertice::y, and s_vvertice::z.

Referenced by get_explicit_desc(), mdpocket_characterize(), and set_pockets_descriptors().

{
        /* Setting atom-based descriptors */
        set_atom_based_descriptors(atoms, natoms, desc, pdb->latoms, pdb->natoms) ;
            
        /* Setting vertice-based descriptors */
        if(! tvert) return ;

        float d = 0.0, vx, vy, vz, vrad,
                  masph_sacc = 0.0, /* Mean alpha sphere solvent accessibility */
                  mean_ashape_radius = 0.0,
                  as_density = 0.0, as_max_dst = -1.0,
                  dtmp = 0.0 ;

        int i, j,
                napol_neigh = 0,
                nAlphaApol = 0 ;
        
        float as_max_r = -1.0 ;

        s_vvertice *vcur = NULL,
                           *vc = NULL ;

        desc->mean_loc_hyd_dens = 0.0 ;
/*
                fprintf(stdout, "\nIn set descripotirs\n") ;
*/
        for(i = 0 ; i < nvert ; i++) {
                vcur = tvert[i] ;
/*
                fprintf(stdout, "Vertice %d: %d %f\n", i, vcur->id, vcur->ray) ;
*/
                if(vcur->ray > as_max_r) as_max_r = vcur->ray ;

                vx = vcur->x ; vy = vcur->y ; vz = vcur->z ; vrad = vcur->ray ;

                /* Calculate apolar density if necessary, and pocket density */
                j = 0 ;
                if(vcur->type == M_APOLAR_AS) {
                        napol_neigh = 0 ;
                        for(j = 0 ; j < nvert ; j++) {
                                vc = tvert[j] ;

                                /* Increment the number of apolar neighbor */
                                if(vc != vcur && vc->type == M_APOLAR_AS &&
                                   dist(vx, vy, vz, vc->x, vc->y, vc->z)-(vc->ray + vrad) <= 0.) {
                                        napol_neigh += 1 ;
                                }

                                /* Update density by the way... */
                                if(j > i) {
                                        dtmp = dist(vcur->x, vcur->y, vcur->z,
                                                                vc->x, vc->y, vc->z);
                                        
                                        if(dtmp > as_max_dst) as_max_dst = dtmp ;
                                        as_density += dtmp ;
                                }
                        }
                        desc->mean_loc_hyd_dens += (float) napol_neigh ;
                        nAlphaApol += 1 ;
                }
                else {
                        /* Update density */
                        for(j = i+1 ; j < nvert ; j++) {
                                dtmp = dist(vcur->x, vcur->y, vcur->z,
                                                        tvert[j]->x, tvert[j]->y, tvert[j]->z) ;
                                
                                if(dtmp > as_max_dst) as_max_dst = dtmp ;
                                as_density += dtmp ;
                        }
                }

                mean_ashape_radius += vcur->ray ;
                /* Estimating solvent accessibility of the sphere */
                d = dist(vcur->x, vcur->y, vcur->z,
                                 vcur->bary[0], vcur->bary[1], vcur->bary[2]) ;
                masph_sacc += d/vcur->ray ;
        }

        if(nAlphaApol>0) desc->mean_loc_hyd_dens /= (float)nAlphaApol ;
        else desc->mean_loc_hyd_dens= 0.0;

        if(flag_do_expensive_calculations) {
            set_ASA(desc, pdb, tvert, nvert);
            desc->volume = get_verts_volume_ptr(tvert, nvert, niter,-1.6) ;
        }
        /*set_ASA(desc,pdb, atoms, natoms, tvert, nvert);*/

        desc->as_max_dst = as_max_dst ;
        desc->apolar_asphere_prop = (float)nAlphaApol / (float)nvert ;
        desc->masph_sacc =  masph_sacc / nvert ;
        desc->mean_asph_ray = mean_ashape_radius / (float)nvert ;
        desc->nb_asph = nvert ;
        desc->as_density = as_density / ((nvert*nvert - nvert) * 0.5) ;

        desc->as_max_r = as_max_r ;
        if (nvert==0){
            desc->apolar_asphere_prop=0.0;
            desc->masph_sacc=0.0;
            desc->mean_asph_ray=0.0;
            desc->as_density=0.0;
        }
}