+def pdb_missing_res(file):
+ msg=''
+ newchain = True
+ ires=[]
+ for line in file:
+ if line[0:6] == 'ATOM ' and line[13:15] == 'CA':
+ i = int(line[22:26])
+ if ires and i==ires[-1]:
+ continue
+ if newchain or i==ires[-1]+1:
+ ires.append(i)
+ newchain = False
+ else:
+ msg = 'chain breaks between residues '+\
+ str(ires[-1])+' and '+str(i)+\
+ ', server cannot add missing residues to PDB file'
+ break
+ if line[0:3] == 'TER':
+ newchain = True
+ if line[0:3] == 'END':
+ break
+
+ return(msg)