Identification of functionally diverse lipocalin proteins from sequence information using support vector machine

Pugalenthi Ganesan, Krishna Kumar Kandaswamy, P. N. Suganthan, G. Archunan, R. Sowdhamini

    Research output: Contribution to journalArticlepeer-review

    9 Scopus citations

    Abstract

    Lipocalins are functionally diverse proteins that are composed of 120-180 amino acid residues. Members of this family have several important biological functions including ligand transport, cryptic coloration, sensory transduction, endonuclease activity, stress response activity in plants, odorant binding, prostaglandin biosynthesis, cellular homeostasis regulation, immunity, immunotherapy and so on. Identification of lipocalins from protein sequence is more challenging due to the poor sequence identity which often falls below the twilight zone. So far, no specific method has been reported to identify lipocalins from primary sequence. In this paper, we report a support vector machine (SVM) approach to predict lipocalins from protein sequence using sequence-derived properties. LipoPred was trained using a dataset consisting of 325 lipocalin proteins and 325 non-lipocalin proteins, and evaluated by an independent set of 140 lipocalin proteins and 21, 447 non-lipocalin proteins. LipoPred achieved 88.61% accuracy with 89.26% sensitivity, 85.27% specificity and 0.74 Matthew's correlation coefficient (MCC). When applied on the test dataset, LipoPred achieved 84.25% accuracy with 88.57% sensitivity, 84.22% specificity and MCC of 0.16. LipoPred achieved better performance rate when compared with PSI-BLAST, HMM and SVM-Prot methods. Out of 218 lipocalins, LipoPred correctly predicted 194 proteins including 39 lipocalins that are non-homologous to any protein in the SWISS-PROT database. This result shows that LipoPred is potentially useful for predicting the lipocalin proteins that have no sequence homologs in the sequence databases. Further, successful prediction of nine hypothetical lipocalin proteins and five new members of lipocalin family prove that LipoPred can be efficiently used to identify and annotate the new lipocalin proteins from sequence databases. The LipoPred software and dataset are available at http://www3.ntu.edu.sg/home/EPNSugan/index-files/lipopred.htm.

    Original languageEnglish (US)
    Pages (from-to)777-783
    Number of pages7
    JournalAmino Acids
    Volume39
    Issue number3
    DOIs
    StatePublished - Aug 1 2010

    Keywords

    • Allergenic proteins
    • Diverse function
    • Ligand binding
    • Lipocalin
    • Odorant binding
    • Salivary proteins
    • Support vector machine

    ASJC Scopus subject areas

    • Biochemistry
    • Clinical Biochemistry
    • Organic Chemistry

    Fingerprint Dive into the research topics of 'Identification of functionally diverse lipocalin proteins from sequence information using support vector machine'. Together they form a unique fingerprint.

    Cite this