Bioinformatics Advance Access published online on April 23, 2009
Bioinformatics, doi:10.1093/bioinformatics/btp257
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Protein function annotation from sequence: prediction of residues interacting with RNA
1Department of Chemistry and Biochemistry, School of Life Sciences, John Maynard-Smith Building, University of Sussex, Falmer, Brighton, BN1 9QG, UK.
2Research Centre for Structural and Functional Proteomics, Institute for Protein Research, Osaka University, Japan.
*To whom correspondence should be addressed. Dr. Susan Jones, E-mail: s.jones{at}sussex.ac.uk
| Abstract |
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Motivation: All eukaryotic proteomes are characterised by a significant percentage of proteins of unknown function. Computational function prediction methods are therefore essential as initial steps in the function annotation process. This paper describes an annotation method (PiRaNhA) for the prediction of RNA-binding residues from protein sequence information. A series of sequence properties (posi-tion specific scoring matrices, interface propensities, predicted ac-cessibility and hydrophobicity) are used to train a support vector machine. This method is then evaluated for its potential to be ap-plied to RNA-binding function prediction at the level of the complete protein.
Results: Five-fold cross-validation of PiRaNhA on a dataset of 81 RNA-binding proteins achieves a Matthews Correlation Coefficient (MCC) of 0.50 and accuracy of 87.2%. When used to predict RNA-binding residues in 42 proteins not used in training, PiRaNhA achieves an MCC of 0.41 and accuracy of 84.5%. Decision values from the PiRaNhA predictions were used in a second SVM to make predictions of RNA-binding function at the protein level, achieving an MCC of 0.53 and accuracy of 76.1%. The PiRaNhA RNA-binding residue predictions allow experimentalists to perform more targeted experiments for function annotation; and the prediction of RNA-binding function at the protein level shows promise for proteome-wide annotations.
Availability and Implementation: Freely available on the web at www.bioinformatics.sussex.ac.uk/PIRANHA or http://piranha.protein.osaka-u.ac.jp.
Contact: s.jones{at}sussex.ac.uk.
Supplementary Information: Supplementary material is available at the journal's web site.
Associate Editor: Prof. Burkhard Rost
Received on January 28, 2009; revised on March 24, 2009; accepted on April 8, 2009