.rnt and .ptt file from genbank

Question

[Molinia]

Hello everyone ! I have a problem with my script to convert genbank file to rnt and ptt file I get inspired by an other post Question : Problem combining ptt, rnt files and I've made some adjustements.

The problem is that when I launch the script for example on NC_008253 it writes that there is no length, no genes and so on.... whereas when I'm printing the value for example the gene 'f.qualifiers['gene'][0]' some are printed and then a KeyError is raised... That's why I tried something on my script to bypass the error

Here it is :

 #!/usr/bin/python3
 import re
 from Bio import SeqIO

 annotation_file = "NC_004431.gb"  # .gbk file
 rnt_file = "NC_004431.rnt"  # .rnt file
 ptt_file = "NC_004431.ptt"  # .ptt file
 r = SeqIO.parse(annotation_file, "gb")
 fasta_file = "NC_004431.fna"

 records = []
 with open(annotation_file) as inpf:
    for rec in SeqIO.parse(inpf, 'genbank'):
       records.append(rec)

 SeqIO.write(records, fasta_file, 'fasta')


 # RNT FILE DEF
 for record in r:
     fasta_file = open(fasta_file, "a")
     SeqIO.write(record, fasta_file, "fasta")
     fasta_file.close()

     record.features = [f for f in record.features if f.type == "rRNA" or f.type == "tRNA"]
     fout = open(rnt_file, "a")
     fout.write("{0} - 1..{1}\n".format(record.description, len(record)))
     fout.write("{0} RNAs\n".format(len(record.features)))
     fout.write("Location\tStrand\tLength\tPID\tGene\tSynonym\tCode\tCOG\tProduct\n")
     strand = {1: '+', -1: '-'}
     for f in record.features:
         try:
             #print(f.qualifiers['gene'])
             fout.write( "{0}\n".format("\t".join([str(abs(f.location.start + 1)) + ".." + str(f.location.end),strrand[f.strand], str(abs(f.location.start - f.location.end)), str(record.annotations['gi']), f.qualifiers['gene'][0], f.qualifiers["locus_tag"][0], '-', '-', f.qualifiers["product"][0]])))

          except KeyError:
             fout.write("{0}\n".format("\t".join([str(abs(f.location.start + 1)) + ".." + str(f.location.end), strand[f.strand], str(abs(f.location.start - f.location.end)), '-', '-', f.qualifiers["locus_tag"][0], '-', '-', f.qualifiers["product"][0]])))

     fout.close()

 # PTT FILE
 r = SeqIO.parse(annotation_file, "gb")
 for record in r:
     record.features = [f for f in record.features if f.type == "CDS"]
     fout = open(ptt_file, "a")
     fout.write("{0} - 1..{1}\n".format(record.description, len(record)))
     fout.write("{0} proteins\n".format(len(record.features)))
     fout.write("Location\tStrand\tLength\tPID\tGene\tSynonym\tCode\tCOG\tProduct\n")
     for f in record.features:
         strand = str(f.strand)
         try:
             product = f.qualifiers["product"][0]
             PID = re.sub('[GI:]', "", str(f.qualifiers['db_xref'][0]))
             translation = f.qualifiers['translation'][0]
             for element in translation:
                 fout.write("{0}\n".format("\t".join([str(abs(f.location.start + 1)) + ".." + str(f.location.end), strand, str(len(element)), PID, f.qualifiers['gene'][0], f.qualifiers["locus_tag"][0], "-", "-", product])))

           except KeyError:
                PID = '-'
                gene = '-'
                product = '-'
                fout.write("{0}\n".format("\t".join([str(abs(f.location.start + 1)) + ".." + str(f.location.end), strand,"-", PID, gene, f.qualifiers["locus_tag"][0], "-", "-", product])))

     fout.close()

I've made an error somewhere but I can't find

Thanks in advance !!

[Mensur Dlakic]

This may not be what you are looking for since it doesn't address the problem with your script, but there are BioPython and BioPerl solutions available.

https://github.com/HenryWiersma/gbkToPttAndRnt

https://github.com/sgivan/gb2ptt

https://github.com/ajvilleg/gbk2ptt

[Molinia]

Thanks for the answer but I have already checked this script

[Molinia]

The problem is that it only write the 'except KeyERROR' part