Research article

Evolution based on domain combinations: the case of glutaredoxins

Rui Alves¹ , Ester Vilaprinyo² , Albert Sorribas¹ and Enrique Herrero¹

¹  Departament de Ciències Mèdiques Bàsiques, Universitat de Lleida, IRBLleida, Montserrat Roig 2, 25008, Lleida, Spain

²  Institut d'Investigació Biomédica de Bellvitge (IDIBELL), Hospitalet de Llobregat, Spain

author email corresponding author email

BMC Evolutionary Biology 2009, 9:66doi:10.1186/1471-2148-9-66

Published:	25 March 2009

Abstract

Background

Protein domains represent the basic units in the evolution of proteins. Domain duplication and shuffling by recombination and fusion, followed by divergence are the most common mechanisms in this process. Such domain fusion and recombination events are predicted to occur only once for a given multidomain architecture. However, other scenarios may be relevant in the evolution of specific proteins, such as convergent evolution of multidomain architectures. With this in mind, we study glutaredoxin (GRX) domains, because these domains of approximately one hundred amino acids are widespread in archaea, bacteria and eukaryotes and participate in fusion proteins. GRXs are responsible for the reduction of protein disulfides or glutathione-protein mixed disulfides and are involved in cellular redox regulation, although their specific roles and targets are often unclear.

Results

In this work we analyze the distribution and evolution of GRX proteins in archaea, bacteria and eukaryotes. We study over one thousand GRX proteins, each containing at least one GRX domain, from hundreds of different organisms and trace the origin and evolution of the GRX domain within the tree of life.

Conclusion

Our results suggest that single domain GRX proteins of the CGFS and CPYC classes have, each, evolved through duplication and divergence from one initial gene that was present in the last common ancestor of all organisms. Remarkably, we identify a case of convergent evolution in domain architecture that involves the GRX domain. Two independent recombination events of a TRX domain to a GRX domain are likely to have occurred, which is an exception to the dominant mechanism of domain architecture evolution.