title: SPdb--a signal peptide database.
abstract: BACKGROUND
  The signal peptide plays an important role in protein targeting and protein translocation in both prokaryotic and eukaryotic cells. This transient, short peptide sequence functions like a postal address on an envelope by targeting proteins for secretion or for transfer to specific organelles for further processing. Understanding how signal peptides function is crucial in predicting where proteins are translocated. To support this understanding, we present SPdb signal peptide database http://proline.bic.nus.edu.sg/spdb, a repository of experimentally determined and computationally predicted signal peptides.
  
  
  RESULTS
  SPdb integrates information from two sources (a) Swiss-Prot protein sequence database which is now part of UniProt and (b) EMBL nucleotide sequence database. The database update is semi-automated with human checking and verification of the data to ensure the correctness of the data stored. The latest release SPdb release 3.2 contains 18,146 entries of which 2,584 entries are experimentally verified signal sequences; the remaining 15,562 entries are either signal sequences that fail to meet our filtering criteria or entries that contain unverified signal sequences.
  
  
  CONCLUSIONS
  SPdb is a manually curated database constructed to support the understanding and analysis of signal peptides. SPdb tracks the major updates of the two underlying primary databases thereby ensuring that its information remains up-to-date.
authors.affiliation: Department of Biochemistry, National University of Singapore, Singapore. justin@bic.nus.edu.sg
authors.forename: Khar Heng
authors.initials: KH
authors.lastname: Choo
authors.forename: Tin Wee
authors.initials: TW
authors.lastname: Tan
authors.forename: Shoba
authors.initials: S
authors.lastname: Ranganathan
mesh_terms: D030561:Databases, Nucleic Acid; D020407:Internet; D010455:Peptides / Q000145:classification; D021382:Protein Sorting Signals / Q000502:physiology*; D021381:Protein Transport / Q000502:physiology; D020539:Sequence Analysis, Protein; D018511:Systems Integration; D014584:User-Computer Interface; D018875:Vocabulary, Controlled
chemical_list: D010455:Peptides; D021382:Protein Sorting Signals