Scroll to navigation

Bio::FeatureIO::ptt(3pm) User Contributed Perl Documentation Bio::FeatureIO::ptt(3pm)


Bio::FeatureIO::ptt - read/write features in PTT format


 # read features 
 my $fin = Bio::FeatureIO->new(-file=>'genes.ptt', -format=>'ptt');
 my @cds;
 while (my $f = $fin->next_feature) {
   push @cds, $f if $f->strand > 0;
 # write features (NOT IMPLEMENTED)
 my $fout = Bio::FeatureIO->new(-fh=>\*STDOUT, -format=>'ptt');
 for my $f (@cds) {


The PTT file format is a table of protein features. It is used mainly by NCBI who produce PTT files for all their published genomes found in <>. It has the following format:

Description of sequence to which the features belong
eg. "Leptospira interrogans chromosome II, complete sequence - 0..358943"

It is usually equivalent to the DEFINITION line of a Genbank file, with the length of the sequence appended. It is unclear why "0" is used as a starting range, it should be "1".

Number of feature lines in the table
eg. "367 proteins"
Column headers, tab separated
eg. "Location Strand Length PID Gene Synonym Code COG Product"

 Location : "begin..end" span of feature
 Strand   : "+" or "-"
 Length   : number of amino acids excluding the stop codon
 PID      : analogous to Genbank /db_xref="GI:xxxxxxxxx"
 Gene     : analogous to Genbank /gene="xxxx"
 Synonym  : analogous to Genbank /locus_tag="xxxx"
 Synonym  : analogous to Genbank /locus_tag="xxxx"
 COG      : CDD COG code with COG letter categories appended
 Product  : analogous to Genbank /product="xxxx"
Feature lines, nine columns, tab separated, "-" used for empty fields
eg. "2491..3423 + 310 24217063 metF LB002 - COG0685E 5,10-methylenetetrahydrofolate reductase"


Mailing Lists

User feedback is an integral part of the evolution of this and other Bioperl modules. Send your comments and suggestions preferably to the Bioperl mailing list. Your participation is much appreciated.                  - General discussion  - About the mailing lists


Please direct usage questions or support issues to the mailing list:

rather than to the module maintainer directly. Many experienced and reponsive experts will be able look at the problem and quickly address it. Please include a thorough description of the problem with code and data examples if at all possible.

Reporting Bugs

Report bugs to the Bioperl bug tracking system to help us keep track of the bugs and their resolution. Bug reports can be submitted via the web:

AUTHOR - Torsten Seemann

Email torsten.seemann AT


Based on and by Allen Day.


The rest of the documentation details each of the object methods. Internal methods are usually preceded with a _


 Title   : _initialize
 Function: Reading? parses the header of the input


 Title   : next_feature
 Usage   : $io->next_feature()
 Function: read the next feature from the PTT file
 Example : 
 Args    : 
 Returns : Bio::SeqFeatureI object

write_feature (NOT IMPLEMENTED)

 Title   : write_feature
 Usage   : $io->write_feature($feature)
 Function: write a Bio::SeqFeatureI object in PTT format
 Example : 
 Args    : Bio::SeqFeatureI object
 Returns :


 Title   : description
 Usage   : $obj->description($newval)
 Function: set/get the PTT file description for/from line one
 Example : 
 Returns : value of description (a scalar)
 Args    : on set, new value (a scalar or undef, optional)


 Title   : protein_count
 Usage   : $obj->protein_count($newval)
 Function: set/get the PTT protein count for/from line two
 Example : 
 Args    : on set, new value (a scalar or undef, optional)
 Returns : value of protein_count (a scalar)
2020-01-13 perl v5.30.0