title: Evolution of the SOUL Heme-Binding Protein Superfamily Across Eukarya.
abstract: SOUL homologs constitute a heme-binding protein superfamily putatively involved in heme and tetrapyrrole metabolisms associated with a number of physiological processes. Despite their omnipresence across the tree of life and the biochemical characterization of many SOUL members, their functional role and the evolutionary events leading to such remarkable protein repertoire still remain cryptic. To explore SOUL evolution, we apply a computational phylogenetic approach, including a relevant number of SOUL homologs, to identify paralog forms and reconstruct their genealogy across the tree of life and within species. In animal lineages, multiple gene duplication or loss events and paralog functional specializations underlie SOUL evolution from the dawn of ancestral echinoderm and mollusc SOUL forms. In photosynthetic organisms, SOUL evolution is linked to the endosymbiosis events leading to plastid acquisition in eukaryotes. Derivative features, such as the F2L peptide and BH3 domain, evolved in vertebrates and provided innovative functionality to support immune response and apoptosis. The evolution of elements such as the N-terminal protein domain DUF2358, the His42 residue, or the tetrapyrrole heme-binding site is modern, and their functional implications still unresolved. This study represents the first in-depth analysis of SOUL protein evolution and provides novel insights in the understanding of their obscure physiological role.
authors.affiliation: Sorbonne Universités, UPMC, Institut de Biologie Paris-Seine, CNRS, Laboratoire de Biologie Computationnelle et Quantitative UMR 7238, 15 rue de l'Ecole de Médecine, 75006, Paris, France. antonio.fortunato@upmc.fr.|Biology and Evolution of Marine Organisms, Stazione Zoologica Anton Dohrn, Villa Comunale, 80121, Naples, Italy. antonio.fortunato@upmc.fr.
authors.forename: Antonio Emidio
authors.initials: AE
authors.lastname: Fortunato
authors.affiliation: Biology and Evolution of Marine Organisms, Stazione Zoologica Anton Dohrn, Villa Comunale, 80121, Naples, Italy.
authors.forename: Paolo
authors.initials: P
authors.lastname: Sordino
authors.affiliation: Australian Institute of Marine Science, PMB N° 3, Townsville MC, QLD, 4810, Australia. n.andreakis@gmail.com.|College of Marine and Environmental Sciences, James Cook University, Townsville, QLD, 4811, Australia. n.andreakis@gmail.com.
authors.forename: Nikos
authors.initials: N
authors.lastname: Andreakis
mesh_terms: D005075:Biological Evolution; D002352:Carrier Proteins / Q000235:genetics*; D030541:Databases, Genetic; D056890:Eukaryota / Q000235:genetics*; D019143:Evolution, Molecular; D020440:Gene Duplication; D000081062:Heme-Binding Proteins; D006420:Hemeproteins / Q000235:genetics*; D010802:Phylogeny; D016415:Sequence Alignment / Q000379:methods; D013559:Symbiosis / Q000235:genetics; D045725:Tetrapyrroles / Q000235:genetics
chemical_list: D002352:Carrier Proteins; D000081062:Heme-Binding Proteins; D006420:Hemeproteins; D045725:Tetrapyrroles
keywords: Apoptosis; Evolution; Heme binding; Light sensing; SOUL; Tetrapyrrole metabolism