1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720
|
/* Copyright (C) 2000, 2001 Damir Zucic */
/*=============================================================================
dihedral_angles.c
Purpose:
Calculate the angles phi, psi, omega, chi1, chi2, chi3 and chi4.
Set the cis-trans flag (0 = bad/undefined, 1 = trans, 2 = cis).
Phi is the angle of the right-handed rotation about N-CA bond.
Phi is to zero if CA-C bond is cis to C-N bond, where the C atom
involved in the C-N bond belongs to the previous residue. Psi is
the angle of the right-handed rotation about CA-C bond. Psi is
zero if C-N bond is cis to N-CA bond, where the N atom involved
in the C-N bond belongs to the next residue. Omega is the angle
of the right-handed rotation about C-N bond. Omega is zero if
CA-C bond is cis to N-CA bond, where both the CA atom and the
C atom involved in the CA-C bond belong to the previous residue.
Chi1 is the angle of the right-handed rotation about CA-CB bond.
Chi1 is zero if CG is cis to N-CA bond. Chi2 is the angle of the
right-handed rotation about CB-CG bond, chi3 about CG-CD bond,
chi4 about CD-CE or CD-NE bond and chi5 is the angle about NE-CZ
bond.
Input:
(1) Pointer to MolComplexS structure.
(2) Pointer to ConfigS structure.
Output:
(1) Dihedral angles calculated, cis-trans flag set.
(2) Return value.
Return value:
(1) Positive on success.
(2) Zero, if complex contains no atoms.
(3) Negative on failure.
Notes:
(1) This should help you to understand phi and psi definitions:
........./................
| H * - * N |
| \ phi1 = 180 |
| * CA | residue 1
| / psi1 = 180 |
| O * - * C |
|........\...............|
| N * - * H |
| / phi2 = 180 |
| CA * | residue 2
| \ psi2 = 180 |
| C * - * O |
|......../...............|
(2) By default, the peptide group has undefined conformation. To
define the peptide group, the coordinates of four atoms are
required.
(3) The peptide bond formed by residues I and I + 1 is assigned
to the residue I + 1. Thus, the cis-trans flag assigned to
the residue I refers to the peptide bond formed by the
residues I - 1 and I. No peptide bond is assigned to the
first residue. The omega angle for the first residue is not
available (undefined).
(4) This function tryes to calculate the phi angle without using
the hydrogen atom coordinates. This means that C atom coord.
of the previous residue are required. It also means that phi
will be missing for the first residue in each chain. In the
second passage, this function will look for hydrogen atoms
in an attempt to calculate the phi angle. If hydrogen atoms
are missing, some phi values may be missing.
(5) The table below contains the list of atoms which are used to
calculate the angles chi1, chi2, chi3, chi4 and chi5:
+-----+-------------+--------------+--------------+-------------+--------------+
| res.| chi1 | chi2 | chi3 | chi4 | chi5 |
|-----+-------------+--------------+--------------+-------------+--------------|
| ALA | | | | | |
| ARG | N-CA-CB-CG | CA-CB-CG-CD | CB-CG-CD-NE | CG-CD-NE-NZ | CD-NE-CZ-NH1 |
| ASN | N-CA-CB-CG | CA-CB-CG-OD1 | | | |
| ASP | N-CA-CB-CG | CA-CB-CG-OD1 | | | |
| CYS | N-CA-CB-SG | | | | |
| GLN | N-CA-CB-CG | CA-CB-CG-CD | CB-CG-CD-OE1 | | |
| GLU | N-CA-CB-CG | CA-CB-CG-CD | CB-CG-CD-OE1 | | |
| GLY | | | | | |
| HIS | N-CA-CB-CG | CA-CB-CG-ND1 | | | |
| ILE | N-CA-CB-CG1 | CA-CB-CG1-CD | | | |
| LEU | N-CA-CB-CD | CA-CB-CG-CD1 | | | |
| LYS | N-CA-CB-CG | CA-CB-CG-CD | CB-CG-CD-CE | CG-CD-CE-NZ | |
| MET | N-CA-CB-CG | CA-CB-CG-SD | CB-CG-SD-CE | | |
| PHE | N-CA-CB-CG | CA-CB-CG-CD1 | | | |
| PRO | N-CA-CB-CG | CA-CB-CG-CD | | | |
| SER | N-CA-CB-OG | | | | |
| THR | N-CA-CB-OG1 | | | | |
| TRP | N-CA-CB-CG | CA-CB-CG-CD1 | | | |
| TYR | N-CA-CB-CG | CA-CB-CG-CD1 | | | |
| VAL | N-CA-CB-CG1 | | | | |
+-----+-------------+--------------+--------------+-------------+--------------+
========includes:============================================================*/
#include <stdio.h>
#include <math.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 ExtractNCAC_ (VectorS *, VectorS *, VectorS *,
AtomS *, size_t, size_t);
int ExtractC_ (VectorS *, AtomS *, size_t, size_t);
double PhiFromCNCAC_ (VectorS *, VectorS *, VectorS *, VectorS *,
ConfigS *);
int ExtractH_ (VectorS *, AtomS *, size_t, size_t);
double PhiFromHNCAC_ (VectorS *, VectorS *, VectorS *, VectorS *);
int ExtractN_ (VectorS *, AtomS *, size_t, size_t);
double PsiFromNCACN_ (VectorS *, VectorS *, VectorS *, VectorS *,
ConfigS *);
int ExtractO_ (VectorS *, AtomS *, size_t, size_t);
double PsiFromNCACO_ (VectorS *, VectorS *, VectorS *, VectorS *);
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 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);
double Chi2FromCACBCGCD_ (AtomS *, size_t, size_t);
double Chi2FromCACBCGOD1_ (AtomS *, size_t, size_t);
double Chi2FromCACBCGND1_ (AtomS *, size_t, size_t);
double Chi2FromCACBCG1CD_ (AtomS *, size_t, size_t);
double Chi2FromCACBCGCD1_ (AtomS *, size_t, size_t);
double Chi2FromCACBCGSD_ (AtomS *, size_t, size_t);
double Chi3FromCBCGCDNE_ (AtomS *, size_t, size_t);
double Chi3FromCBCGCDOE1_ (AtomS *, size_t, size_t);
double Chi3FromCBCGCDCE_ (AtomS *, size_t, size_t);
double Chi3FromCBCGSDCE_ (AtomS *, size_t, size_t);
double Chi4FromCGCDNECZ_ (AtomS *, size_t, size_t);
double Chi4FromCGCDCENZ_ (AtomS *, size_t, size_t);
double Chi5FromCDNECZNH1_ (AtomS *, size_t, size_t);
/*======calculate dihedral angles and set the cis-trans flag:================*/
int DihedralAngles_ (MolComplexS *mol_complexSP, ConfigS *configSP)
{
int residuesN, residueI;
size_t vector_struct_size;
int n;
ResidueS *current_residueSP;
size_t current_startI, current_endI;
static VectorS N_vectorS, CA_vectorS, C_vectorS;
ResidueS *previous_residueSP;
size_t previous_startI, previous_endI;
static VectorS previousCA_vectorS, previousC_vectorS;
static VectorS H_vectorS;
ResidueS *next_residueSP;
size_t next_startI, next_endI;
static VectorS nextN_vectorS;
static VectorS O_vectorS;
double cis_abs_omega_max;
double trans_abs_omega_min;
double abs_omega;
int cis_transF = 0;
AtomS *first_atomSP;
char *residue_nameP;
int residue_typeI;
/* Return zero if there are no atoms: */
if (mol_complexSP->atomsN == 0) return 0;
/* Prepare and check the number of residues - at least one is required: */
residuesN = mol_complexSP->residuesN;
if (residuesN < 1) return -1;
/* The size of VectorS structure: */
vector_struct_size = sizeof (VectorS);
/*---------------------------------------------------------------------------*/
/* The first passage: initialize dihedral angles and cis-trans flag. */
for (residueI = 0; residueI < residuesN; residueI++)
{
/* Pointer to the current residue: */
current_residueSP = mol_complexSP->residueSP + residueI;
/* Initialize all dihedral angles: */
current_residueSP->phi = BADDIHEDANGLE;
current_residueSP->psi = BADDIHEDANGLE;
current_residueSP->omega = BADDIHEDANGLE;
current_residueSP->chi1 = BADDIHEDANGLE;
current_residueSP->chi2 = BADDIHEDANGLE;
current_residueSP->chi3 = BADDIHEDANGLE;
current_residueSP->chi4 = BADDIHEDANGLE;
/* Initialize the cis-trans flag: */
current_residueSP->cis_transF = 0;
}
/*---------------------------------------------------------------------------*/
/* The second passage: calculate phi and psi. */
for (residueI = 0; residueI < residuesN; residueI++)
{
/* Pointer to the current residue: */
current_residueSP = mol_complexSP->residueSP + residueI;
/* Prepare the atomic index range for the current residue: */
current_startI = current_residueSP->residue_startI;
current_endI = current_residueSP->residue_endI;
/* Try to extract N, CA and C coordinates for the current residue: */
n = ExtractNCAC_ (&N_vectorS, &CA_vectorS, &C_vectorS,
mol_complexSP->atomSP, current_startI, current_endI);
/* If the coordinates of any atom are missing, */
/* it is not possible to calculate phi and psi: */
if (n < 3) continue;
/*------phi:---------------------------------------------------------*/
/* The first attempt - use the coordinates of the */
/* C atom from the previous residue, if available: */
do
{
/* Do nothing for the first residue: */
if (residueI < 1) break;
/* 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;
/* Try to extract the C atom */
/* from the previous residue: */
n = ExtractC_ (&previousC_vectorS,
mol_complexSP->atomSP,
previous_startI, previous_endI);
if (n < 1) break;
/* If the C atom coordinates are available for */
/* the previous residue, try to calculate phi: */
current_residueSP->phi = PhiFromCNCAC_ (&previousC_vectorS,
&N_vectorS,
&CA_vectorS,
&C_vectorS,
configSP);
} while (0);
/* The second attempt - use the coordinates of the */
/* H atom from the current residue, if available: */
do
{
/* If phi was determined before, */
/* this attempt is not required: */
if (current_residueSP->phi != BADDIHEDANGLE) break;
/* Try to extract the H atom coordinates: */
n = ExtractH_ (&H_vectorS,
mol_complexSP->atomSP,
current_startI, current_endI);
if (n < 1) break;
/* If the H atom coordinates are available for */
/* the current residue, try to calculate phi: */
current_residueSP->phi = PhiFromHNCAC_ (&H_vectorS,
&N_vectorS,
&CA_vectorS,
&C_vectorS);
} while (0);
/*------psi:---------------------------------------------------------*/
/* The first attempt - use the coordinates of the */
/* N atom from the next residue, if available: */
do
{
/* Do nothing for the last residue: */
if (residueI >= residuesN - 1) break;
/* Pointer to the next residue: */
next_residueSP = mol_complexSP->residueSP + residueI + 1;
/* The atomic index range for the next residue: */
next_startI = next_residueSP->residue_startI;
next_endI = next_residueSP->residue_endI;
/* Try to extract the N atom */
/* from the next residue: */
n = ExtractN_ (&nextN_vectorS,
mol_complexSP->atomSP,
next_startI, next_endI);
if (n < 1) break;
/* If the N atom coordinates are available for */
/* the next residue, try to calculate psi: */
current_residueSP->psi = PsiFromNCACN_ (&N_vectorS,
&CA_vectorS,
&C_vectorS,
&nextN_vectorS,
configSP);
} while (0);
/* The second attempt - use the coordinates of the */
/* O atom from the current residue, if available: */
do
{
/* If psi was determined before, */
/* this attempt is not required: */
if (current_residueSP->psi != BADDIHEDANGLE) break;
/* Try to extract the O atom coordinates: */
n = ExtractO_ (&O_vectorS,
mol_complexSP->atomSP,
current_startI, current_endI);
if (n < 1) break;
/* If the O atom coordinates are available for */
/* the current residue, try to calculate psi: */
current_residueSP->psi = PsiFromNCACO_ (&N_vectorS,
&CA_vectorS,
&C_vectorS,
&O_vectorS);
} while (0);
}
/*---------------------------------------------------------------------------*/
/* Initialize ranges for omega: */
/* Cis range: */
cis_abs_omega_max = DEG_TO_RAD * OMEGA_TOLERANCE;
trans_abs_omega_min = DEG_TO_RAD * (180.0 - OMEGA_TOLERANCE);
/* The third passage: calculate omega and */
/* cis-trans flag. Skip the first residue. */
for (residueI = 1; residueI < residuesN; residueI++)
{
/* Pointer to the current residue: */
current_residueSP = mol_complexSP->residueSP + residueI;
/* Prepare the atomic index range for the current residue: */
current_startI = current_residueSP->residue_startI;
current_endI = current_residueSP->residue_endI;
/* 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;
/* Pointer to the previous residue: */
previous_residueSP = mol_complexSP->residueSP + residueI - 1;
/* The atomic index range from 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;
/* Try to calculate omega: */
current_residueSP->omega = OmegaFromCACNCA_ (&previousCA_vectorS,
&previousC_vectorS,
&N_vectorS,
&CA_vectorS,
configSP);
/* Prepare the cis-trans flag: */
abs_omega = fabs (current_residueSP->omega);
if (abs_omega < cis_abs_omega_max) cis_transF = 2;
else if (abs_omega > trans_abs_omega_min) cis_transF = 1;
else cis_transF = 0;
current_residueSP->cis_transF = cis_transF;
}
/*---------------------------------------------------------------------------*/
/* The fourth passage: calculate side chain torsion angles (chi1 etc.). */
for (residueI = 0; residueI < residuesN; residueI++)
{
/* Pointer to the current residue: */
current_residueSP = mol_complexSP->residueSP + residueI;
/* The atomic index range for the current residue: */
current_startI = current_residueSP->residue_startI;
current_endI = current_residueSP->residue_endI;
/* Pointer to the first atom of the current residue: */
first_atomSP = mol_complexSP->atomSP + current_startI;
/* The name of the current residue: */
residue_nameP = first_atomSP->raw_atomS.pure_residue_nameA;
/* Check is the current residue from */
/* the set of 20 standard residues: */
residue_typeI = IsStandard_ (residue_nameP);
/*------chi1:--------------------------------------------------------*/
/* Calculate chi1: */
switch (residue_typeI)
{
/* Do nothing for ALA and GLY: */
case 0: /* ALA */
case 7: /* GLY */
break;
/* Use N, CA, CB and CG for ARG, ASN, ASP, GLN, */
/* GLU, HIS, LEU, LYS, MET, PHE, PRO, 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 14: /* PRO */
case 17: /* TRP */
case 18: /* TYR */
current_residueSP->chi1 =
Chi1FromNCACBCG_ (mol_complexSP->atomSP,
current_startI,
current_endI);
break;
/* Use N, CA, CB and SG for CYS: */
case 4: /* CYS */
current_residueSP->chi1 =
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 */
current_residueSP->chi1 =
Chi1FromNCACBCG1_ (mol_complexSP->atomSP,
current_startI,
current_endI);
break;
/* Use N, CA, CB and OG for SER: */
case 15: /* SER */
current_residueSP->chi1 =
Chi1FromNCACBOG_ (mol_complexSP->atomSP,
current_startI,
current_endI);
break;
/* Use N, CA, CB and OG1 for THR: */
case 16: /* THR */
current_residueSP->chi1 =
Chi1FromNCACBOG1_ (mol_complexSP->atomSP,
current_startI,
current_endI);
break;
/* At present, chi1 is not calculated for exotic residues: */
default:
;
}
/*------chi2:--------------------------------------------------------*/
/* Calculate chi2: */
switch (residue_typeI)
{
/* Do nothing for ALA, CYS, GLY, SER, THR and VAL: */
case 0: /* ALA */
case 4: /* CYS */
case 7: /* GLY */
case 15: /* SER */
case 16: /* THR */
case 19: /* VAL */
break;
/* Use CA, CB, CG and CD for ARG, GLN, GLU, LYS and PRO: */
case 1: /* ARG */
case 5: /* GLN */
case 6: /* GLU */
case 11: /* LYS */
case 14: /* PRO */
current_residueSP->chi2 =
Chi2FromCACBCGCD_ (mol_complexSP->atomSP,
current_startI,
current_endI);
break;
/* Use CA, CB, CG and OD1 for ASN and ASP: */
case 2: /* ASN */
case 3: /* ASP */
current_residueSP->chi2 =
Chi2FromCACBCGOD1_ (mol_complexSP->atomSP,
current_startI,
current_endI);
break;
/* Use CA, CB, CG and ND1 for HIS: */
case 8: /* HIS */
current_residueSP->chi2 =
Chi2FromCACBCGND1_ (mol_complexSP->atomSP,
current_startI,
current_endI);
break;
/* Use CA, CB, CG1 and CD for ILE: */
case 9: /* ILE */
current_residueSP->chi2 =
Chi2FromCACBCG1CD_ (mol_complexSP->atomSP,
current_startI,
current_endI);
break;
/* Use CA, CB, CG and CD1 for LEU, PHE, TRP and TYR: */
case 10: /* LEU */
case 13: /* PHE */
case 17: /* TRP */
case 18: /* TYR */
current_residueSP->chi2 =
Chi2FromCACBCGCD1_ (mol_complexSP->atomSP,
current_startI,
current_endI);
break;
/* Use CA, CB, CG and SD for MET: */
case 12: /* MET */
current_residueSP->chi2 =
Chi2FromCACBCGSD_ (mol_complexSP->atomSP,
current_startI,
current_endI);
break;
/* At present, chi2 is not calculated for exotic residues: */
default:
;
}
/*------chi3:--------------------------------------------------------*/
/* Calculate chi3: */
switch (residue_typeI)
{
/* Do nothing for ALA, ASN, ASP, CYS, GLY, HIS, */
/* ILE, LEU, PHE, PRO, SER THR, TRP, TYR and VAL: */
case 0: /* ALA */
case 2: /* ASN */
case 3: /* ASP */
case 4: /* CYS */
case 7: /* GLY */
case 8: /* HIS */
case 9: /* ILE */
case 10: /* LEU */
case 13: /* PHE */
case 14: /* PRO */
case 15: /* SER */
case 16: /* THR */
case 17: /* TRP */
case 18: /* TYR */
case 19: /* VAL */
break;
/* Use CB, CG, CD and NE for ARG: */
case 1: /* ARG */
current_residueSP->chi3 =
Chi3FromCBCGCDNE_ (mol_complexSP->atomSP,
current_startI,
current_endI);
break;
/* Use CB, CG, CD and OE1 for GLN and GLU: */
case 5: /* GLN */
case 6: /* GLU */
current_residueSP->chi3 =
Chi3FromCBCGCDOE1_ (mol_complexSP->atomSP,
current_startI,
current_endI);
break;
/* Use CB, CG, CD and CE for LYS: */
case 11: /* LYS */
current_residueSP->chi3 =
Chi3FromCBCGCDCE_ (mol_complexSP->atomSP,
current_startI,
current_endI);
break;
/* Use CB, CG, SD and CE for MET: */
case 12: /* MET */
current_residueSP->chi3 =
Chi3FromCBCGSDCE_ (mol_complexSP->atomSP,
current_startI,
current_endI);
break;
/* At present, chi3 is not calculated for exotic residues: */
default:
;
}
/*------chi4:--------------------------------------------------------*/
/* Calculate chi4: */
switch (residue_typeI)
{
/* Do nothing for ALA, ASN, ASP, CYS, GLN, GLU, GLY, HIS, */
/* ILE, LEU, MET, PHE, PRO, SER, THR, TRP, TYR and VAL: */
case 0:
case 2:
case 3:
case 4:
case 5:
case 6:
case 7:
case 8:
case 9:
case 10:
case 12:
case 13:
case 14:
case 15:
case 16:
case 17:
case 18:
case 19:
break;
/* Use CG, CD, NE and CZ for ARG: */
case 1: /* ARG */
current_residueSP->chi4 =
Chi4FromCGCDNECZ_ (mol_complexSP->atomSP,
current_startI,
current_endI);
break;
/* Use CG, CD, NE and CZ for LYS: */
case 11:
current_residueSP->chi4 =
Chi4FromCGCDCENZ_ (mol_complexSP->atomSP,
current_startI,
current_endI);
break;
/* At present, chi4 is not calculated for exotic residues: */
default:
;
}
/*------chi5:--------------------------------------------------------*/
/* Calculate chi5: */
switch (residue_typeI)
{
/* Do nothing for ALA, ASN, ASP, CYS, GLN, GLU, GLY, HIS, */
/* ILE, LEU, LYS, MET, PHE, PRO, SER, THR, TRP, TYR and VAL: */
case 0:
case 2:
case 3:
case 4:
case 5:
case 6:
case 7:
case 8:
case 9:
case 10:
case 11:
case 12:
case 13:
case 14:
case 15:
case 16:
case 17:
case 18:
case 19:
break;
/* Use CD, NE, CZ and NH1 for ARG: */
case 1: /* ARG */
current_residueSP->chi5 =
Chi5FromCDNECZNH1_ (mol_complexSP->atomSP,
current_startI,
current_endI);
break;
/* At present, chi5 is not calculated for exotic residues: */
default:
;
}
}
/*---------------------------------------------------------------------------*/
/* If this point is reached, return the positive value (success indicator): */
return 1;
}
/*===========================================================================*/
|