In this report, we describe a novel tandem peptide repeat protein, Eicosapentapeptide repeat (EPR), which occurs notably only in flowering plants. The EPRs are characterized by a 25 amino acid repeat unit, X2CX4CX10CX2HGGG, repeated 10 times tandemly. Sequence search revealed that the repeat motif is highly conserved across its occurrence. EPRs are predicted to exist as quasi-globular stable structures owing to highly conserved amino acid positions and potential disulfide bridges. Proteins containing EPRs are predicted to be located in chloroplasts; non-enzymatic and peptide or DNA-binding in molecular function; and they are possibly involved in transcription regulation.#R##N##R##N#Contact: jnagaraju@cdfd.org.in#R##N##R##N#Supplementary information: Architecture, identifiers and annotations of EPRs; search parameters, distribution and sequence alignment; 2D structure prediction and disulfide connectivity are provided as pdf files S1--S8, at Bioinformatics online.
['Sunil Archak', 'Javaregowda Nagaraju']
Eicosapentapeptide repeats (EPRs): novel repeat proteins specific to flowering plants