Réimplémentation du programme DSSP en Python

atom.py 18KB

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  1. import math
  2. from structure import *
  3. class Atom:
  4. def dist_atoms(self, atom2):
  5. return(math.sqrt((self.coord_x-atom2.coord_x)**2 +
  6. (self.coord_y-atom2.coord_y)**2 +
  7. (self.coord_z-atom2.coord_z)**2))
  8. def __init__(self, atom_id, atom_name, res_name, chain_id,
  9. res_seq_nb, insertion_code, coordinates):
  10. self.atom_id = atom_id
  11. self.atom_name = atom_name
  12. self.res_name = res_name
  13. self.chain_id = chain_id
  14. self.res_seq_nb = res_seq_nb
  15. self.insertion_code = insertion_code
  16. self.coord_x = coordinates[0]
  17. self.coord_y = coordinates[1]
  18. self.coord_z = coordinates[2]
  19. self.coords = coordinates
  20. class Residue:
  21. def __init__(self, atoms_list, indice):
  22. self.atoms = {}
  23. for atom in atoms_list:
  24. self.atoms[atom.atom_name] = atom
  25. self.resid = atom.res_seq_nb
  26. self.res_name = atom.res_name
  27. self.res_letter = self.get_amino_letter(atom.res_name)
  28. self.chain_id = atom.chain_id
  29. self.insertion_code = atom.insertion_code
  30. self.indice = indice
  31. def get_amino_letter(self, res_name):
  32. code3 = ['ALA', 'ARG', 'ASN', 'ASP', 'CYS', 'GLU', 'GLN', 'GLY',
  33. 'HIS', 'ILE', 'LEU', 'LYS', 'MET', 'PHE', 'PRO', 'SER',
  34. 'THR', 'TRP', 'TYR', 'VAL']
  35. code1 = ['A','R','N','D','C','E','Q','G','H','I','L','K','M','F','P',
  36. 'S','T','W','Y','V']
  37. return code1[code3.index(res_name)]
  38. def h_bond(self, res2):
  39. if("H" not in res2.atoms.keys()):
  40. return(False)
  41. # dimensionnal factor, in kcal/mole
  42. f = 332
  43. # partial charges
  44. q1 = 0.42
  45. q2 = 0.20
  46. # distance between O-N atoms, in angströms
  47. r_ON = self.atoms["O"].dist_atoms(res2.atoms["N"])
  48. # distance between C-H atoms, in angströms
  49. r_CH = self.atoms["C"].dist_atoms(res2.atoms["H"])
  50. # distance between O-H atoms, in angströms
  51. r_OH = self.atoms["O"].dist_atoms(res2.atoms["H"])
  52. # distance between C-N atoms, in angströms
  53. r_CN = self.atoms["C"].dist_atoms(res2.atoms["N"])
  54. # electrostatic interaction energy, in kcal/mole
  55. E = q1*q2*(1/r_ON + 1/r_CH - 1/r_OH - 1/r_CN)*f
  56. return(E)
  57. def get_turns(self, residues):
  58. """
  59. Get all the turns from a specific residue.
  60. """
  61. turns = {}
  62. i = residues.index(self)
  63. k = 0
  64. for j in range(3,6):
  65. if(i+j<len(residues)):
  66. if(self.h_bond(residues[i+j])<-0.5):
  67. k = j
  68. if k != 0:
  69. #print(k,"TURN", residues[i].resid, residues[i+k].resid)
  70. return Turn(k,residues[i].resid)
  71. return False
  72. def get_bends(self, residues):
  73. i = residues.index(self)
  74. if i >=2 and i <len(residues)-2:
  75. angle = math.degrees(vector_angles(vectors_substr(position_vector(residues[i].atoms["CA"].coords),
  76. position_vector(residues[i-2].atoms["CA"].coords)),
  77. vectors_substr(position_vector(residues[i+2].atoms["CA"].coords),
  78. position_vector(residues[i].atoms["CA"].coords))))
  79. if(angle>70):
  80. return [angle, 'S']
  81. return [angle, '']
  82. else:
  83. return [360.0, '']
  84. def get_bridges(self, residues):
  85. bridges = {}
  86. bridge = {}
  87. strongest_bridge = {}
  88. i = residues.index(self)
  89. if(i >= 1 and i < len(residues)-4):
  90. E_min = 0
  91. for j in range(i+2,len(residues)-1):
  92. # select triplet with the minimal energy
  93. if(residues[i-1].h_bond(residues[j])<-0.5
  94. and residues[j].h_bond(residues[i+1])<-0.5):
  95. bridge = {'res1':residues[i-1].h_bond(residues[j]),
  96. 'res2':residues[j].h_bond(residues[i+1]),
  97. 'ipos':residues[i].resid,
  98. 'jpos':residues[j].resid,
  99. 'btype':"para"}
  100. if(residues[j-1].h_bond(residues[i])<-0.5
  101. and residues[i].h_bond(residues[j+1])<-0.5):
  102. bridge = {'res1':residues[j-1].h_bond(residues[i]),
  103. 'res2':residues[i].h_bond(residues[j+1]),
  104. 'ipos':residues[i].resid,
  105. 'jpos':residues[j].resid,
  106. 'btype':"para"}
  107. if(residues[i].h_bond(residues[j])<-0.5
  108. and residues[j].h_bond(residues[i])<-0.5):
  109. bridge = {'res1':residues[i].h_bond(residues[j]),
  110. 'res2':residues[j].h_bond(residues[i]),
  111. 'ipos':residues[i].resid,
  112. 'jpos':residues[j].resid,
  113. 'btype':"anti"}
  114. if(residues[i-1].h_bond(residues[j+1])<-0.5
  115. and residues[j-1].h_bond(residues[i+1])<-0.5):
  116. bridge = {'res1':residues[i-1].h_bond(residues[j+1]),
  117. 'res2':residues[j-1].h_bond(residues[i+1]),
  118. 'ipos':residues[i].resid,
  119. 'jpos':residues[j].resid,
  120. 'btype':"anti"}
  121. if(bridge):
  122. if(bridge['res1']+bridge['res2']<E_min):
  123. E_min = bridge['res1']+bridge['res2']
  124. strongest_bridge = bridge
  125. bridge = {}
  126. coord_bridge = [i,j]
  127. # finally add the strongest bridge at i and j pos
  128. if(strongest_bridge):
  129. bridges[coord_bridge[0]] = (Bridge(strongest_bridge['btype'],
  130. strongest_bridge['ipos'],
  131. strongest_bridge['jpos']))
  132. bridges[coord_bridge[1]] = (Bridge(strongest_bridge['btype'],
  133. strongest_bridge['jpos'],
  134. strongest_bridge['ipos']))
  135. if(len(bridges)>0):
  136. return(bridges[coord_bridge[0]])
  137. else:
  138. return(False)
  139. def get_helix(self, residues):
  140. """
  141. Return if there is an helix at a given residue,
  142. as well as its type.
  143. """
  144. i = residues.index(self)
  145. # if there are no turns or it is the first residue, skip
  146. if i == 0:
  147. return False
  148. if(self.get_turns(residues) and residues[i-1].get_turns(residues)):
  149. #print(self.get_turns(residues).turn_type,"- HELIX at", residues[i].indice)
  150. return(self.get_turns(residues).turn_type, residues[i].indice)
  151. return(False)
  152. def get_ladder(self, residues):
  153. #ladders = {}
  154. i = residues.index(self)
  155. if i != 0:
  156. if self.get_bridges(residues):
  157. if (residues[i-1].get_bridges(residues)):
  158. local_bridge = self.get_bridges(residues)
  159. consec_bridge = residues[i-1].get_bridges(residues)
  160. if local_bridge.bridge_type == consec_bridge.bridge_type:
  161. #print("ladder", consec_bridge.res_num, local_bridge.res_num)
  162. ladder = {'start':consec_bridge.res_num,
  163. 'end':local_bridge.res_num,
  164. 'bridges':[consec_bridge, local_bridge]}
  165. return ladder
  166. return False
  167. def get_tco(self, residues):
  168. i = residues.index(self)
  169. if(i!=0):
  170. res2 = residues[i-1]
  171. CO_res1 = vector_from_pos(self.atoms["C"].coords,
  172. self.atoms["O"].coords)
  173. CO_res2 = vector_from_pos(res2.atoms["C"].coords,
  174. res2.atoms["O"].coords)
  175. angle = vector_angles(CO_res1, CO_res2)
  176. else:
  177. angle = math.pi/2
  178. return(math.cos(angle))
  179. def get_chirality(self, residues):
  180. i = residues.index(self)
  181. if (i >=1 and i < len(residues)-2):
  182. chirality = {}
  183. angle = calc_dihedral(residues[i-1].atoms["CA"].coords,
  184. residues[i].atoms["CA"].coords,
  185. residues[i+1].atoms["CA"].coords,
  186. residues[i+2].atoms["CA"].coords)
  187. if(angle>0 and angle<=180):
  188. sign="+"
  189. if(angle<=0 and angle > -180):
  190. sign="-"
  191. else:
  192. angle = 360.0
  193. sign = ''
  194. return [angle, sign]
  195. def get_phi_psi(self, residues):
  196. i = residues.index(self)
  197. if(i==0):
  198. phi = 360.0
  199. else:
  200. phi = calc_dihedral(residues[i-1].atoms["C"].coords,
  201. residues[i].atoms["N"].coords,
  202. residues[i].atoms["CA"].coords,
  203. residues[i].atoms["C"].coords)
  204. if(i==len(residues)-1):
  205. psi = 360.0
  206. else:
  207. psi = calc_dihedral(residues[i].atoms["N"].coords,
  208. residues[i].atoms["CA"].coords,
  209. residues[i].atoms["C"].coords,
  210. residues[i+1].atoms["N"].coords)
  211. return((phi, psi))
  212. def get_bridges(residues):
  213. bridges = {}
  214. bridge = {}
  215. strongest_bridge = {}
  216. for i in range(1,len(residues)-4):
  217. E_min = 0
  218. for j in range(i+2,len(residues)-1):
  219. # select triplet with the minimal energy
  220. if(residues[i-1].h_bond(residues[j])<-0.5
  221. and residues[j].h_bond(residues[i+1])<-0.5):
  222. bridge = {'res1':residues[i-1].h_bond(residues[j]),
  223. 'res2':residues[j].h_bond(residues[i+1]),
  224. 'ipos':residues[i].resid,
  225. 'jpos':residues[j].resid,
  226. 'i':residues[i].indice,
  227. 'j':residues[j].indice,
  228. 'btype':"para"}
  229. if(residues[j-1].h_bond(residues[i])<-0.5
  230. and residues[i].h_bond(residues[j+1])<-0.5):
  231. bridge = {'res1':residues[j-1].h_bond(residues[i]),
  232. 'res2':residues[i].h_bond(residues[j+1]),
  233. 'ipos':residues[i].resid,
  234. 'jpos':residues[j].resid,
  235. 'i':residues[i].indice,
  236. 'j':residues[j].indice,
  237. 'btype':"para"}
  238. if(residues[i].h_bond(residues[j])<-0.5
  239. and residues[j].h_bond(residues[i])<-0.5):
  240. bridge = {'res1':residues[i].h_bond(residues[j]),
  241. 'res2':residues[j].h_bond(residues[i]),
  242. 'ipos':residues[i].resid,
  243. 'jpos':residues[j].resid,
  244. 'i':residues[i].indice,
  245. 'j':residues[j].indice,
  246. 'btype':"anti"}
  247. if(residues[i-1].h_bond(residues[j+1])<-0.5
  248. and residues[j-1].h_bond(residues[i+1])<-0.5):
  249. bridge = {'res1':residues[i-1].h_bond(residues[j+1]),
  250. 'res2':residues[j-1].h_bond(residues[i+1]),
  251. 'ipos':residues[i].resid,
  252. 'jpos':residues[j].resid,
  253. 'i':residues[i].indice,
  254. 'j':residues[j].indice,
  255. 'btype':"anti"}
  256. if(bridge):
  257. if(bridge['res1']+bridge['res2']<E_min):
  258. E_min = bridge['res1']+bridge['res2']
  259. strongest_bridge = bridge
  260. coord_bridge = [i,j]
  261. bridge = {}
  262. # finally add the strongest bridge at i and j pos
  263. if(strongest_bridge):
  264. bridges[strongest_bridge['i']] = (Bridge(strongest_bridge['btype'],
  265. strongest_bridge['ipos'],
  266. strongest_bridge['jpos'],
  267. [strongest_bridge['i'],
  268. strongest_bridge['j']]))
  269. bridges[strongest_bridge['j']] = (Bridge(strongest_bridge['btype'],
  270. strongest_bridge['ipos'],
  271. strongest_bridge['jpos'],
  272. [strongest_bridge['i'],
  273. strongest_bridge['j']]))
  274. if(len(bridges)>0):
  275. return(bridges)
  276. else:
  277. return(False)
  278. def get_ladders(bridges, residues):
  279. ladders = {}
  280. i = 1
  281. while i < len(residues):
  282. k = 1
  283. if i in bridges.keys():
  284. temp_bridges = [bridges[i]]
  285. while ((i+k in bridges.keys()) and
  286. (bridges[i].bridge_type == bridges[i+k].bridge_type)):
  287. temp_bridges.append(bridges[i+k])
  288. k+=1
  289. if k>1:
  290. #print("ladder", bridges[i].res_num, bridges[i+k-1].res_num)
  291. ladders[i] = {'start':bridges[i].res_num,
  292. 'end':bridges[i+k-1].res_num,
  293. 'bridges':temp_bridges,
  294. 'i':i,
  295. 'j':i+k-1}
  296. i+=k-1
  297. else:
  298. i+=1
  299. return ladders
  300. def connected_ladders(ladd_1, ladd_2):
  301. links = []
  302. for bridge in ladd_1['bridges']:
  303. if bridge.res_partner in res_list(ladd_2):
  304. return ladd_2
  305. return False
  306. def connected_ladders2(ladd_1, ladd_2):
  307. links = []
  308. for bridge in ladd_1['bridges']:
  309. if bridge.res_partner in res_list(ladd_2):
  310. return([ladd_1['i'], ladd_1['j'], bridge.i, bridge.j,
  311. ladd_2['i'], ladd_2['j']])
  312. #return ladd_2
  313. return False
  314. def get_sheets(ladders):
  315. """
  316. Bridges between ladders.
  317. Check if 1 bridge between one ladder and one or more other ladders.
  318. Iterate over all residues of one ladder and check if bridge with other residues
  319. of the other ladders.
  320. """
  321. ladds = [ elem for elem in ladders.values() ]
  322. sheets = {}
  323. corresp = {}
  324. for ladd1 in ladds:
  325. for ladd2 in ladds:
  326. if connected_ladders(ladd1, ladd2)!=False:
  327. corresp_list = [ elem for elem in corresp.keys() ]
  328. if ladd1['i'] not in corresp_list and ladd2['i'] not in corresp_list:
  329. ind = len(sheets.keys())
  330. sheets[ind] = []
  331. sheets[ind].append(ladd1)
  332. sheets[ind].append(ladd2)
  333. corresp[ladd1['i']] = ind
  334. corresp[ladd2['i']] = ind
  335. elif ladd2 not in corresp_list and ladd1 in corresp_list:
  336. sheets[corresp[ladd1['i']]].append(ladd2)
  337. corresp[ladd2['i']] = corresp[ladd1['i']]
  338. elif ladd1 not in corresp_list and ladd2 in corresp_list:
  339. sheets[corresp[ladd2['i']]].append(ladd1)
  340. corresp[ladd1['i']] = corresp[ladd2['i']]
  341. return sheets
  342. def get_sheets2(ladders):
  343. """
  344. Bridges between ladders.
  345. Check if 1 bridge between one ladder and one or more other ladders.
  346. Iterate over all residues of one ladder and check if bridge with other residues
  347. of the other ladders.
  348. """
  349. sheets = {}
  350. for ladder in ladders:
  351. for ladd2 in ladders:
  352. if connected_ladders(ladders[ladder], ladders[ladd2]):
  353. bridge_i = connected_ladders2(ladders[ladder], ladders[ladd2])[2]
  354. bridge_j = connected_ladders2(ladders[ladder], ladders[ladd2])[3]
  355. print("ladder",ladders[ladder]['i'], ladders[ladder]['j'],"bridge",bridge_i, bridge_j,
  356. "ladder 2",ladders[ladd2]['i'], ladders[ladd2]['j'])
  357. def res_list(ladder):
  358. # TODO : method in ladder class
  359. l=[]
  360. for i in range(ladder['i'], ladder['j']):
  361. l.append(i)
  362. return(l)
  363. def build_turns_patterns(residues):
  364. turns_3 = {}
  365. turns_4 = {}
  366. turns_5 = {}
  367. for i,res in enumerate(residues):
  368. turn = residues[i].get_turns(residues)
  369. if(turn):
  370. for k in range(turn.turn_type):
  371. if turn.turn_type == 3:
  372. turns_3[i+1+k] = turn.turn_type
  373. if turn.turn_type == 4:
  374. turns_4[i+1+k] = turn.turn_type
  375. if turn.turn_type == 5:
  376. turns_5[i+1+k] = turn.turn_type
  377. return[turns_3, turns_4, turns_5]
  378. def build_helix_patterns(residues):
  379. helix_3 = {}
  380. helix_4 = {}
  381. helix_5 = {}
  382. for i,res in enumerate(residues):
  383. helix = residues[i].get_helix(residues)
  384. if(helix):
  385. helix_type = residues[i].get_helix(residues)[0]
  386. helix_pos = residues[i].get_helix(residues)[1]
  387. #print("TYPE", helix_type)
  388. for k in range(helix_type):
  389. if helix_type == 3:
  390. helix_3[i+1+k] = "G"
  391. if helix_type == 4:
  392. helix_4[i+1+k] = "H"
  393. if helix_type == 5:
  394. helix_5[i+1+k] = "I"
  395. #print(helix_3)
  396. return[helix_3, helix_4, helix_5]
  397. def print_helix_pattern(residues, res, helix):
  398. i = residues.index(res)+1
  399. if i in helix.keys():
  400. return (helix[i])
  401. else:
  402. return(' ')
  403. def print_turn_pattern(residues, res, turns):
  404. i = residues.index(res)+1
  405. if i in turns.keys() and not i-1 in turns.keys():
  406. return(">")
  407. elif i in turns.keys() and i-1 in turns.keys():
  408. return(turns[i])
  409. elif i not in turns.keys() and i-1 in turns.keys():
  410. return("<")
  411. else:
  412. return(' ')