| Autor: |
Meza AN; Department of Microbiology, Institute of Biomedical Sciences, Applied Structural Biology Laboratory, LBEA, University of São Paulo, São Paulo, SP, Brazil.; Institute of Biology, Post-graduate Program in Genetics and Molecular Biology, University of Campinas, UNICAMP, Campinas, SP, Brazil., Cambui CCN; Department of Microbiology, Institute of Biomedical Sciences, Applied Structural Biology Laboratory, LBEA, University of São Paulo, São Paulo, SP, Brazil., Moreno ACR; Department of Microbiology, Vaccine Development Laboratory, Biomedical Sciences Institute, University of São Paulo, São Paulo, SP, Brazil., Fessel MR; Department of Microbiology, Institute of Biomedical Sciences, Applied Structural Biology Laboratory, LBEA, University of São Paulo, São Paulo, SP, Brazil., Balan A; Department of Microbiology, Institute of Biomedical Sciences, Applied Structural Biology Laboratory, LBEA, University of São Paulo, São Paulo, SP, Brazil. abalan@usp.br. |
| Abstrakt: |
Cyanide is a toxic compound that is converted to the non-toxic thiocyanate by a rhodanese enzyme. Rhodaneses belong to the family of transferases (sulfurtransferases), which are largely studied. The sulfur donor defines the subfamily of these enzymes as thiosulfate:cyanide sulfurtransferases or rhodaneses (TSTs) or 3-mercaptopyruvate sulfurtransfeases (MSTs). In Mycobacterium tuberculosis, the causative agent of tuberculosis, the gene Rv0815c encodes the protein CysA2, a putative uncharacterized thiosulfate:cyanide sulfurtransferase that belongs to the essential sulfur assimilation pathway in the bacillus and is secreted during infection. In this work, we characterized the functional and structural properties of CysA2 and its kinetic parameters. The recombinant CysA2 is a α/β protein with two rhodanese-like domains that maintains the functional motifs and a catalytic cysteine. Sulfurtransferase activity was determined using thiosulfate and 3-mercaptopyruvate as sulfur donors. The assays showed K m values of 2.89 mM and 7.02 mM for thiosulfate and 3-mercaptopyruvate, respectively, indicating the protein has dual activity as TST and MST. Immunological assays revealed that CysA2 interacted with pulmonary cells, and it was capable to activate macrophages and dendritic cells, indicating the stimulation of the immune response, which is important for its use as an antigen for vaccine development and immunodiagnostic. |
