title: Prediction of glutathionylation sites in proteins using minimal sequence information and their experimental validation.
abstract: S-glutathionylation of proteins plays an important role in various biological processes and is known to be protective modification during oxidative stress. Since, experimental detection of S-glutathionylation is labor intensive and time consuming, bioinformatics based approach is a viable alternative. Available methods require relatively longer sequence information, which may prevent prediction if sequence information is incomplete. Here, we present a model to predict glutathionylation sites from pentapeptide sequences. It is based upon differential association of amino acids with glutathionylated and non-glutathionylated cysteines from a database of experimentally verified sequences. This data was used to calculate position dependent F-scores, which measure how a particular amino acid at a particular position may affect the likelihood of glutathionylation event. Glutathionylation-score (G-score), indicating propensity of a sequence to undergo glutathionylation, was calculated using position-dependent F-scores for each amino-acid. Cut-off values were used for prediction. Our model returned an accuracy of 58% with Matthew's correlation-coefficient (MCC) value of 0.165. On an independent dataset, our model outperformed the currently available model, in spite of needing much less sequence information. Pentapeptide motifs having high abundance among glutathionylated proteins were identified. A list of potential glutathionylation hotspot sequences were obtained by assigning G-scores and subsequent Protein-BLAST analysis revealed a total of 254 putative glutathionable proteins, a number of which were already known to be glutathionylated. Our model predicted glutathionylation sites in 93.93% of experimentally verified glutathionylated proteins. Outcome of this study may assist in discovering novel glutathionylation sites and finding candidate proteins for glutathionylation.
authors.affiliation: a Radiation Biology & Health Sciences Division, Bio-Medical Group , Bhabha Atomic Research Centre , Trombay , Mumbai , India ;
authors.forename: Debojyoti
authors.initials: D
authors.lastname: Pal
authors.affiliation: a Radiation Biology & Health Sciences Division, Bio-Medical Group , Bhabha Atomic Research Centre , Trombay , Mumbai , India ;
authors.forename: Deepak
authors.initials: D
authors.lastname: Sharma
authors.affiliation: b Solid State Physics Division, Physics Group , Bhabha Atomic Research Centre , Trombay , Mumbai , India.
authors.forename: Mukesh
authors.initials: M
authors.lastname: Kumar
authors.affiliation: a Radiation Biology & Health Sciences Division, Bio-Medical Group , Bhabha Atomic Research Centre , Trombay , Mumbai , India ;
authors.forename: Santosh K
authors.initials: SK
authors.lastname: Sandur
mesh_terms: D019295:Computational Biology; D003545:Cysteine / Q000378:metabolism*; D005978:Glutathione / Q000378:metabolism*; D018384:Oxidative Stress; D011506:Proteins / Q000378:metabolism*
chemical_list: D011506:Proteins; D005978:Glutathione; D003545:Cysteine
keywords: Cysteine; S-glutathionylation; oxidative stress; prediction; protein modification