title: Non-random distribution of homo-repeats: links with biological functions and human diseases.
abstract: The biological function of multiple repetitions of single amino acids, or homo-repeats, is largely unknown, but their occurrence in proteins has been associated with more than 20 hereditary diseases. Analysing 122 bacterial and eukaryotic genomes, we observed that the number of proteins containing homo-repeats is significantly larger than expected from theoretical estimates. Analysis of statistical significance indicates that the minimal size of homo-repeats varies with amino acid type and proteome. In an attempt to characterize proteins harbouring long homo-repeats, we found that those containing polar or small amino acids S, P, H, E, D, K, Q and N are enriched in structural disorder as well as protein- and RNA-interactions. We observed that E, S, Q, G, L, P, D, A and H homo-repeats are strongly linked with occurrence in human diseases. Moreover, S, E, P, A, Q, D and T homo-repeats are significantly enriched in neuronal proteins associated with autism and other disorders. We release a webserver for further exploration of homo-repeats occurrence in human pathology at http://bioinfo.protres.ru/hradis/.
authors.affiliation: Group of Bioinformatics, Institute of Protein Research, Russian Academy of Sciences, 4 Institutskaya str., Pushchino, Moscow Region, 142290, Russia.
authors.forename: Michail Yu
authors.initials: MY
authors.lastname: Lobanov
authors.affiliation: Bioinformatics and Genomics Programme, Centre for Genomic Regulation (CRG), Dr Aiguader 88, 08003 Barcelona, Spain.
authors.forename: Petr
authors.initials: P
authors.lastname: Klus
authors.affiliation: Group of Bioinformatics, Institute of Protein Research, Russian Academy of Sciences, 4 Institutskaya str., Pushchino, Moscow Region, 142290, Russia.
authors.forename: Igor V
authors.initials: IV
authors.lastname: Sokolovsky
authors.affiliation: Bioinformatics and Genomics Programme, Centre for Genomic Regulation (CRG), Dr Aiguader 88, 08003 Barcelona, Spain.|Universitat Pompeu Fabra (UPF), 08003 Barcelona, Spain.|Institució Catalana de Recerca i Estudis Avançats (ICREA), 23 Passeig Lluís Companys, 08010 Barcelona, Spain.
authors.forename: Gian Gaetano
authors.initials: GG
authors.lastname: Tartaglia
authors.affiliation: Group of Bioinformatics, Institute of Protein Research, Russian Academy of Sciences, 4 Institutskaya str., Pushchino, Moscow Region, 142290, Russia.
authors.forename: Oxana V
authors.initials: OV
authors.lastname: Galzitskaya
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics; D030541:Databases, Genetic; D063990:Gene Ontology; D020022:Genetic Predisposition to Disease; D006801:Humans; D020543:Proteome / Q000235:genetics; D020449:Repetitive Sequences, Amino Acid / Q000235:genetics*; D020539:Sequence Analysis, Protein
chemical_list: D001426:Bacterial Proteins; D020543:Proteome