UniProtKB/TrEMBL - Old Release Notes
N.B. From release 27, the UniProtKB/TrEMBL release notes are included in the UniProt release notes.
TrEMBL Release Notes
Release 8, November 1998
European Bioinformatics Institute (EBI)
Wellcome Trust Genome Campus
Cambridge CB10 1SD
Telephone: (+44 1223) 494 444
Fax: (+44 1223) 494 468
Electronic mail address: DATALIB@EBI.AC.UK
WWW server: http://www.ebi.ac.uk/
Swiss Institute of Bioinformatics (SIB)
Centre Medical Universitaire
1, rue Michel Servet
1211 Geneva 4
Telephone: (+41 22) 784 40 82
Fax: (+41 22) 702 55 02
Electronic mail address: BAIROCH@CMU.UNIGE.CH
WWW server: http://www.expasy.ch/
TrEMBL has been prepared by:
o Rolf Apweiler, Sergio Contrino, Wolfgang Fleischmann, Gill Fraser,
Henning Hermjakob, Vivien Junker, Stephanie Kappus, Youla
Karavidopoulou, Fiona Lang, Michele Magrane, Maria Jesus Martin,
Steffen Moeller, Nicoletta Mitaritonna and Claire O'Donovan at
the EMBL Outstation - European Bioinformatics Institute (EBI) in
o Amos Bairoch and Alain Gateau at the Swiss Institute of Bioinformatics
in Geneva, Switzerland.
This manual and the database it accompanies may be copied and
redistributed freely, without advance permission, provided
that this statement is reproduced with each copy.
If you want to cite TrEMBL in a publication please use the
Bairoch A., and Apweiler R.
The Swiss-Prot protein sequence data bank and its
supplement TrEMBL in 1998.
Nucleic Acids Res. 26:38-42(1998).
TrEMBL is a computer-annotated protein sequence database supplementing the
Swiss-Prot Protein Sequence Data Bank. TrEMBL contains the translations of
all coding sequences (CDS) present in the EMBL Nucleotide Sequence Database
not yet integrated in Swiss-Prot. TrEMBL can be considered as a preliminary
section of Swiss-Prot. For all TrEMBL entries which should finally be
upgraded to the standard Swiss-Prot quality, Swiss-Prot accession numbers
have been assigned.
2. Why a supplement to Swiss-Prot?
The ongoing gene sequencing and mapping projects have dramatically
increased the number of protein sequences to be incorporated into Swiss-Prot.
We do not want to dilute the quality standards of Swiss-Prot by incorporating
sequences without proper sequence analysis and annotation, but we do want to
make the sequences available as fast as possible. TrEMBL achieves this second
goal, and is a major step in the process of speeding up subsequent
upgrading of annotation to the standard Swiss-Prot quality.
To address the problem of redundancy, the translations of all coding
sequences (CDS) in the EMBL Nucleotide Sequence Database already included
in Swiss-Prot have been removed from TrEMBL.
We name this supplement TrEMBL (Translation from EMBL), since the tools
used to create the translations of the CDS are based on the program
'trembl' written by Thure Etzold at the EMBL.
3. The Release
This TrEMBL release is created from the EMBL Nucleotide Sequence Database
release 56 and contains 224'543 sequence entries, comprising 60'188'661 amino
acids. To minimise redundancy, the translations of all coding sequences (CDS)
in the EMBL Nucleotide Sequence Database already included in Swiss-Prot 36
have been removed from TrEMBL release 8.
TrEMBL is split in two main sections; SP-TrEMBL and REM-TrEMBL:
SP-TrEMBL (Swiss-Prot TrEMBL) contains the entries (180'763) which should be
eventually incorporated into Swiss-Prot. Swiss-Prot accession numbers have
been assigned for all SP-TrEMBL entries.
SP-TrEMBL is organised in subsections:
arc.dat (Archea): 7397 entries
fun.dat (Fungi): 6007 entries
hum.dat (Human): 7688 entries
inv.dat (Invertebrates): 22829 entries
mam.dat (Other Mammals): 2892 entries
mhc.dat (MHC proteins): 3985 entries
org.dat (Organelles): 14230 entries
phg.dat (Bacteriophages): 1824 entries
pln.dat (Plants): 14749 entries
pro.dat (Prokaryotes): 39777 entries
rod.dat (Rodents): 6923 entries
unc.dat (Unclassified): 44 entries
vrl.dat (Viruses): 48472 entries
vrt.dat (Other Vertebrates): 3946 entries
20'082 new entries have been integrated in SP-TrEMBL. 922 sequences of
SP-TrEMBL entries have been updated and in 124'261 cases the annotation
has been updated.
In the document deleteac.txt you will find a list of all accession numbers
which appeared earlier in the TrEMBL data bank, but have been deleted from the
REM-TrEMBL (REMaining TrEMBL) contains the entries (43'780) that we do
not want to include in Swiss-Prot. REM-TrEMBL entries have no accession
numbers. This section is organised in five subsections:
1) Immunoglobulins and T-cell receptors (Immuno.dat)
Most REM-TrEMBL entries are immunoglobulins and T-cell receptors. We
stopped entering immunoglobulins and T-cell receptors into Swiss-Prot,
because we only want to keep the germ line gene derived translations
of these proteins in Swiss-Prot and not all known somatic recombinated
variations of these proteins. We would like to create a specialised
database dealing with these sequences as a further supplement to
Swiss-Prot and keep only a representative cross-section of these
proteins in Swiss-Prot.
2) Synthetic sequences (Synth.dat)
Another category of data, which will not be included in Swiss-Prot are
synthetic sequences. Again, we do not want to leave these entries in
TrEMBL. Ideally one should build a specialised database for artificial
sequences as a further supplement to Swiss-Prot.
3) Patent application sequences (Patent.dat)
A third subsection consists of coding sequences captured from patent
applications. A thorough survey of these entries have shown that
apart from a rather small minority (which in most cases have already
been integrated in Swiss-Prot), most of these sequences contain either
erroneous data or concern artificially generated sequences outside the
scope of Swiss-Prot.
4) Small fragments (Smalls.dat)
Another subsection consists of fragments with less than eight amino
5) CDS not coding for real proteins (Pseudo.dat)
The last subsection consists of CDS translations where we have strong
evidence to believe that these CDS are not coding for real proteins.
4. Format Differences Between Swiss-Prot and TrEMBL
The format and conventions used by TrEMBL follow as closely as possible
that of Swiss-Prot. Hence, it is not necessary to produce an additional
user manual and extensive release notes for TrEMBL. The information given
in the Swiss-Prot release notes and user manual are in general valid for
TrEMBL. The differences are mentioned below.
The general structure of an entry is identical in Swiss-Prot and TrEMBL.
The data class used in TrEMBL (in the ID line) is always 'PRELIMINARY',
whereas in Swiss-Prot it is always 'STANDARD'.
Differences in line types present in Swiss-Prot and TrEMBL:
The ID line (IDentification):
The entry name used in SP-TrEMBL is the same as the Accession Number of the
entry. The entry name used in REM-TrEMBL is the PID tagged to the
corresponding CDS in the EMBL Nucleotide Sequence Database. 'PID' stands for
the "Protein IDentification" number. It is a number that you will find in
EMBL nucleotide sequence entries in a qualifier called "/db_xref" which is
tagged to every CDS in the nucleotide database. Example:
FT CDS 54..1382
FT /note="ribulose-1,5-bisphosphate carboxylase/
FT oxygenase activase precursor"
The DT line (DaTe)
The format of the DT lines that serve to indicate when an entry was
created and updated are identical to that defined in Swiss-Prot; but the
DT lines in TrEMBL are referring to the TEMBL release. The difference is
shown in the example below.
DT lines in a Swiss-Prot entry:
DT 01-JAN-1988 (REL. 06, CREATED)
DT 01-JUL-1989 (REL. 11, LAST SEQUENCE UPDATE)
DT 01-AUG-1992 (REL. 23, LAST ANNOTATION UPDATE)
DT lines in a TrEMBL entry:
DT 01-NOV-1996 (TREMBLREL. 01, CREATED)
DT 01-NOV-1996 (TREMBLREL. 01, LAST SEQUENCE UPDATE)
DT 01-FEB-1997 (TREMBLREL. 02, LAST ANNOTATION UPDATE)
5. Weekly updates of TrEMBL and non-redundant data sets
Weekly cumulative updates of TrEMBL are available by anonymous FTP and
from the EBI SRS server.
We also produce every week a complete non-redundant protein sequence
collection by providing three compressed files (these are in the directory
/pub/databases/sp_tr_nrdb on the EBI FTP server and in databases/sp_tr_nrdb
on the ExPASy server): sprot.dat.Z, trembl.dat.Z and trembl_new.dat.Z.
This set of non-redundant files is especially important for two types of
(i) Managers of similarity search services. They can now provide what is
currently the most comprehensive and non-redundant data set of protein
(ii) Anybody wanting to update their full copy of Swiss-Prot + TrEMBL to
their own schedule without having to wait for full releases of Swiss-Prot
or of TrEMBL.
6. Access/Data Distribution
FTP server: ftp.ebi.ac.uk/pub/databases/trembl
SRS server: http://srs.ebi.ac.uk/
TrEMBL is also available on the Swiss-Prot CD-ROM.
Swiss-Prot + TrEMBL is searchable on the following servers at the EBI:
7. Description of changes made to TrEMBL since release 7.
7.1 Switch to the NCBI taxonomy
To standardise the taxonomies used by different databases we have switched
to the NCBI taxonomy, which is already used by the DDBJ/EMBL/GenBank
nucleotide sequence databases.
7.2 Introduction of RT lines
We have introduced a new line type, the RT (Reference Title) line.
This optional line is placed between the RA and RL line. The RT line gives the
title of the paper (or other work) as accurately as possible given the limitations
of the computer character set. The form used is that which is used in a
citation rather than that displayed at the top of the published paper. For
instance, where journals capitalise major title words this is not preserved.
The title is enclosed in double quotes, and may continue over several
lines if necessary. Note these lines are in mixed case. The title lines are
terminated by a semicolon. An example of the use of RT lines is shown below:
RT "Sequence analysis of the genome of the unicellular cyanobacterium
RT Synechocystis sp. strain PCC6803. I. Sequence features in the 1 Mb
RT region from map positions 64% to 92% of the genome.";
8. Planned changes
8.1 Extension of the accession number system
As explained in detail in the Swiss-Prot release notes under 2.3, we will
extend the accession number system when the 'O' series is used up. This can
be anticipated for January 1999.