RESUMO
We characterized an operon in Mycobacterium tuberculosis, Rv3679-Rv3680, in which each open reading frame is annotated to encode "anion transporter ATPase" homologues. Using structure prediction modeling, we found that Rv3679 and Rv3680 more closely resemble the guided entry of tail-anchored proteins 3 (Get3) chaperone in eukaryotes. Get3 delivers proteins into the membranes of the endoplasmic reticulum and is essential for the normal growth and physiology of some eukaryotes. We sought to characterize the structures of Rv3679 and Rv3680 and test if they have a role in M. tuberculosis pathogenesis. We solved crystal structures of the nucleotide-bound Rv3679-Rv3680 complex at 2.5 to 3.2 Å and show that while it has some similarities to Get3 and ArsA, there are notable differences, including that these proteins are unlikely to be involved in anion transport. Deletion of both genes did not reveal any conspicuous growth defects in vitro or in mice. Collectively, we identified a new class of proteins in bacteria with similarity to Get3 complexes, the functions of which remain to be determined.IMPORTANCE Numerous bacterial species encode proteins predicted to have similarity with Get3- and ArsA-type anion transporters. Our studies provide evidence that these proteins, which we named BagA and BagB, are unlikely to be involved in anion transport. In addition, BagA and BagB are conserved in all mycobacterial species, including the causative agent of leprosy, which has a highly decayed genome. This conservation suggests that BagAB constitutes a part of the core mycobacterial genome and is needed for some yet-to-be-determined part of the life cycle of these organisms.
Assuntos
Proteínas de Bactérias/química , Proteínas de Bactérias/genética , Mycobacterium tuberculosis/química , Mycobacterium tuberculosis/genética , Adenosina Trifosfatases/química , Adenosina Trifosfatases/genética , Animais , Proteínas de Transporte de Ânions/genética , Feminino , Genoma Bacteriano , Fatores de Troca do Nucleotídeo Guanina/química , Fatores de Troca do Nucleotídeo Guanina/genética , Camundongos , Camundongos Endogâmicos C57BL , Modelos Moleculares , Óperon , Ligação Proteica , Conformação Proteica , Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/química , Proteínas de Saccharomyces cerevisiae/genéticaRESUMO
The URA3 gene of Debaryomyces hansenii, encoding orotidine 5'-phosphate decarboxylase enzyme, was isolated by complementation in the yeast Saccharomyces cerevisiae. The deduced amino acid sequence is highly similar to Ura3 proteins from other yeast and fungal species. Analysis of the region upstream of the coding sequence revealed the presence of AG-rich minisatellite DNA sequences. In addition, upstream of the DURA3 sequence, we have found the 3'-terminal of a gene encoding a GEA2-like protein.