Mycobacterium tuberculosis CysA2 is a dual sulfurtransferase with activity against thiosulfate and 3-mercaptopyruvate and interacts with mammalian cells

A N Meza,M R Fessel,A Balan,C C N Cambui,A C R Moreno

doi:10.1038/s41598-019-53069-6

A N Meza, M R Fessel + Show 3 more

Open Access

https://doi.org/10.1038/s41598-019-53069-6

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Abstract

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 Km 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.

Highlights

Mycobacterium tuberculosis is the causative agent of the tuberculosis, one of the most common life-threatening infectious diseases worldwide, which effective treatment is still under concerning[1,2]
thiosulfate:cyanide sulfurtransferases or rhodaneses (TSTs) and mercaptopyruvate sulfurtransfeases (MSTs) belong to group II of tandem domain proteins that is formed by two rhodanese domains, one being active and the other inactive[12]
M. tuberculosis cysA2 gene encodes one of four putative thiosulfate sulfurtransferases found in the bacillus genome

Summary

Introduction

Mycobacterium tuberculosis is the causative agent of the tuberculosis, one of the most common life-threatening infectious diseases worldwide, which effective treatment is still under concerning[1,2]. The sulfur assimilation pathway in M. tuberculosis involves the sulfate uptake system SubICysTWA1, an ATP-Binding Cassette (ABC) transporter, and the sequential activity of a set of enzymes (CysCDNHI) that will generate L-cysteine for further synthesis of methionine, mycothiol and cofactors[4]. Since this pathway is only present in bacteria, it becomes an important mechanism to target aiming the inhibition of bacterial oxidative stress, host infection and establishment of long-term infections[5,6]. The genome analysis of M. tuberculosis showed four genes encoding proteins with rhodanese (TST) domains: cysA2 (Rv0815c), cysA3 (Rv3117), sseA (Rv3283) and sseB (Rv2291). We explored the characterization of its immunogenic properties showing that CysA2 can bind to lung cells (TC-1) of C57BL/6 mice, and to activate murine macrophages J774 and spleen dendritic cells

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