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Apr 12, 2021: PSORTb will be unavailable for at least four days during the week of April 19, 2021 for major scheduled maintenance (transitioning to a new database and hardware). It will not be possible to submit new jobs for email analysis during this period. This update will provide stability fixes, security improvements, and updates to some of the underlying software. Please note that the BLAST version used has been updated and minor variations in the output from this tool should be expected as a result. If you have any questions or concerns, please do not hesitate to contact us at We apologize for any inconvenience and thank you for your understanding as we implement this major upgrade.


Submit a Sequence to PSORTb version 3.0.2

Based on a study last performed in 2010, PSORTb v3.0.2 is the most precise bacterial localization prediction tool available. PSORTb v3.0.2 has a number of improvements over PSORTb v2.0.4. Version 2 of PSORTb is maintained here.

You can currently submit one or more Gram-positive or Gram-negative bacterial sequences or archaeal sequences in FASTA format (?). Copy and paste your FASTA-formatted sequences into the textbox below or select a file containing your sequences to upload from your computer. Web display mode is limited to the analysis of approximately 100 proteins. For larger analyses, either enter your email address in the form below (results of up to 5000 per submission returned by email) or for even larger analyses we can help you or you can download the standalone version.

See also:

Choose an organism type (?):
Choose Gram stain (?):
Advanced Gram stain options (?):
Output format (?):
Show results (?):
Email address:

Copy and paste your FASTA sequences below

or upload from file:
(uploads limited to 50KB, approximately 100 proteins, in Web display mode, enter an email address to use email mode if you need to analyze more proteins)

This is the most current version of the PSORTb program for bacterial protein subcellular localization prediction. PSORTb v3.0 now handles archaeal sequences as well as Gram-positive and Gram-negative bacterial sequences. Plus, it has several other improvements. Version 2 of PSORTb is maintained here (but we strongly recommend using version 3.0! ;-). If you are looking for a eukaryotic localization predictor, please visit to access other resources.  
PSORTb is maintained by the Brinkman Laboratory, Simon Fraser University, British Columbia, Canada. If you use PSORTb in your research, we would greatly appreciate if you cited one of the following publications, and note the version of software you use:
  • PSORTb v3.0: N.Y. Yu, J.R. Wagner, M.R. Laird, G. Melli, S. Rey, R. Lo, P. Dao, S.C. Sahinalp, M. Ester, L.J. Foster, F.S.L. Brinkman (2010) PSORTb 3.0: Improved protein subcellular localization prediction with refined localization subcategories and predictive capabilities for all prokaryotes, Bioinformatics 26(13):1608-1615
  • PSORTb v2.0: J.L. Gardy, M.R. Laird, F. Chen, S. Rey, C.J. Walsh, M. Ester, and F.S.L. Brinkman (2005) PSORTb v.2.0: expanded prediction of bacterial protein subcellular localization and insights gained from comparative proteome analysis, Bioinformatics 21(5):617-623
  • PSORTb v1.0: Jennifer L. Gardy, Cory Spencer, Ke Wang, Martin Ester, Gabor E. Tusnady, Istvan Simon, Sujun Hua, Katalin deFays, Christophe Lambert, Kenta Nakai and Fiona S.L. Brinkman (2003) PSORT-B: improving protein subcellular localization prediction for Gram-negative bacteria, Nucleic Acids Research 31(13):3613-17

If you are interested in being notified about changes in the status of PSORTb, please subscribe to the psort-update mailing list by emailing with "subscribe psort-update" in the subject or body of the message.


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