Calatayud, SaraGarcia-Risco, MarioPalacios, ÒscarCapdevila Vidal, MercèCañestro García, CristianAlbalat Rodríguez, Ricard2022-02-242022-09-272021-09-270737-4038https://hdl.handle.net/2445/183503To investigate novel patterns and processes of protein evolution, we have focused in the metallothioneins (MTs), a singular group of metal-binding, cysteine-rich proteins that, due to their high degree of sequence diversity, still represents a 'black hole' in Evolutionary Biology. We have identified and analyzed more than 160 new MTs in nonvertebrate chordates (especially in 37 species of ascidians, 4 thaliaceans, and 3 appendicularians) showing that prototypic tunicate MTs are mono-modular proteins with a pervasive preference for cadmium ions, whereas vertebrate and cephalochordate MTs are bimodular proteins with diverse metal preferences. These structural and functional differences imply a complex evolutionary history of chordate MTs-including de novo emergence of genes and domains, processes of convergent evolution, events of gene gains and losses, and recurrent amplifications of functional domains-that would stand for an unprecedented case in the field of protein evolution.14 p.application/pdfengcc by-nc (c) Calatayud, Sara et al., 2021http://creativecommons.org/licenses/by-nc/3.0/es/CordatsUrocordatsChordataTunicatainfo:eu-repo/semantics/article7191152022-02-24info:eu-repo/semantics/openAccess