Functional characterization of two members of histidine phosphatase superfamily in Mycobacterium tuberculosis

Abstract

BackgroundFunctional characterization of genes in important pathogenic bacteria such as Mycobacterium tuberculosis is imperative. Rv2135c, which was originally annotated as conserved hypothetical, has been found to be associated with membrane protein fractions of H37Rv strain. The gene appears to contain histidine phosphatase motif common to both cofactor-dependent phosphoglycerate mutases and acid phosphatases in the histidine phosphatase superfamily. The functions of many of the members of this superfamily are annotated based only on similarity to known proteins using automatic annotation systems, which can be erroneous. In addition, the motif at the N-terminal of Rv2135c is ‘RHA’ unlike ‘RHG’ found in most members of histidine phosphatase superfamily. These necessitate the need for its experimental characterization. The crystal structure of Rv0489, another member of the histidine phosphatase superfamily in M. tuberculosis, has been previously reported. However, its biochemical characteristics remain unknown. In this study, Rv2135c and Rv0489 from M. tuberculosis were cloned and expressed in Escherichia coli with 6 histidine residues tagged at the C terminal.ResultsCharacterization of the purified recombinant proteins revealed that Rv0489 possesses phosphoglycerate mutase activity while Rv2135c does not. However Rv2135c has an acid phosphatase activity with optimal pH of 5.8. Kinetic parameters of Rv2135c and Rv0489 are studied, confirming that Rv0489 is a cofactor dependent phosphoglycerate mutase of M. tuberculosis. Additional characterization showed that Rv2135c exists as a tetramer while Rv0489 as a dimer in solution.ConclusionMost of the proteins orthologous to Rv2135c in other bacteria are annotated as phosphoglycerate mutases or hypothetical proteins. It is possible that they are actually phosphatases. Experimental characterization of a sufficiently large number of bacterial histidine phosphatases will increase the accuracy of the automatic annotation systems towards a better understanding of this important group of enzymes.

Metabolic switching and cell wall remodelling of Mycobacterium tuberculosis during bone tuberculosis

“…Acid phosphatases secreted from osteoclast cells are considered a key marker of bone resorption, as they dissolve both organic (collagen) and inorganic (calcium and phosphorus) components of bone 45 . Rv2577 , which encodes a secreted acid phosphatase 46,47 containing a TAT (twin arginine translocation) motif was also found to be overexpressed, suggesting a potential role in bone resorption. Additionally, several genes ( mce1A, Rv3717, glmU and Rv0296c ) considered important for invasion of mycobacteria into host tissues were also induced in the present study.…”

Structural and Substrate Interaction Properties of Alkaline Phosphatase from Paenibacillus sp. PSB04: In-Silico Analysis

“…Meanwhile, Acid Phosphatase (AcP) and AP also attack the ester bond of other P compounds at different pH environments and release inorganic P as the byproduct. AcP and AP catalyze optimally in acidic and alkaline conditions, respectively (Coker et al, 2013). Unlike AP, most AcP does not utilize metal ions during catalysis except for tartrate group AcP.…”

Involvement of Leishmania Phosphatases in Parasite Biology and Pathogeny

“…The histidine acid phosphatase (HAcP) superfamily is a large family of proteins with a conserved catalytic histidine residue in the motif RHG present at the N-terminus, which becomes phosphorylated during the reaction (Rigden, 2008;Coker et al, 2013). Their substrate specificity has not been ascertained; therefore, they do not belong to the classical STP or PTP families (Soulat and Bogdan, 2017).…”