Abstract:Mycobacterium tuberculosis is the cause of the world’s most deadly infectious disease. Efforts are underway to target the methionine biosynthesis pathway, as it is not part of the host metabolism. The homoserine transacetylase MetX converts l-homoserine to O-acetyl-l-homoserine at the committed step of this pathway. In order to facilitate structure-based drug design, we determined the high-resolution crystal structures of three MetX proteins, including M. tuberculosis (MtMetX), Mycolicibacterium abscessus (MaM… Show more
“…This direct sulfurylation is catalyzed by acylhomoserine transferase enzymes that are the products of genes most commonly annotated as metY and sometimes as metZ ( 3 ). Confusingly, the equivalent gene is named metC in Mycobacterium species, including Mycobacterium tuberculosis ( 10 , 11 ). Figure 1 Bacterial methionine biosynthesis pathways.…”
This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
“…This direct sulfurylation is catalyzed by acylhomoserine transferase enzymes that are the products of genes most commonly annotated as metY and sometimes as metZ ( 3 ). Confusingly, the equivalent gene is named metC in Mycobacterium species, including Mycobacterium tuberculosis ( 10 , 11 ). Figure 1 Bacterial methionine biosynthesis pathways.…”
This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
“…For docking studies, the three-dimensional structures of HSAT homologs from M. tuberculosis (PDB id: 6PUX) and S. aureus (PDB id: 4QLO) were downloaded from PDB 44 , 45 . AutoDock-Tools were used for preparing the protein structures, determining the target regions for ligand binding and analysing the docking results 46 , 47 .…”
There is an urgent need to validate new drug targets and identify small molecules that possess activity against both drug-resistant and drug-sensitive bacteria. The enzymes belonging to amino acid biosynthesis have been shown to be essential for growth in vitro, in vivo and have not been exploited much for the development of anti-tubercular agents. Here, we have identified small molecule inhibitors targeting homoserine acetyl transferase (HSAT, MetX, Rv3341) from M. tuberculosis. MetX catalyses the first committed step in L-methionine and S-adenosyl methionine biosynthesis resulting in the formation of O-acetyl-homoserine. Using CRISPRi approach, we demonstrate that conditional repression of metX resulted in inhibition of M. tuberculosis growth in vitro. We have determined steady state kinetic parameters for the acetylation of L-homoserine by Rv3341. We show that the recombinant enzyme followed Michaelis–Menten kinetics and utilizes both acetyl-CoA and propionyl-CoA as acyl-donors. High-throughput screening of a 2443 compound library resulted in identification of small molecule inhibitors against MetX enzyme from M. tuberculosis. The identified lead compounds inhibited Rv3341 enzymatic activity in a dose dependent manner and were also active against HSAT homolog from S. aureus. Molecular docking of the identified primary hits predicted residues that are essential for their binding in HSAT homologs from M. tuberculosis and S. aureus. ThermoFluor assay demonstrated direct binding of the identified primary hits with HSAT proteins. Few of the identified small molecules were able to inhibit growth of M. tuberculosis and S. aureus in liquid cultures. Taken together, our findings validated HSAT as an attractive target for development of new broad-spectrum anti-bacterial agents that should be effective against drug-resistant bacteria.
“…MetX/A. The homoserine transacetylase of M. tuberculosis is predicted in silico to be highly ligandable (Chaton et al, 2019). Using FTMap algorithm, they managed to find numerous consensus sites (CS) that reside within the active site of MetX.…”
Section: Targets Of the Aspartate Pathwaymentioning
Recent research has been conducted to find potential new avenues of drug discovery for treating tuberculosis infection. This endless “arms race” is due to the ability of the bacteria to develop resistance towards the already established antibiotic regimen. Various pathways within Mycobacterium tuberculosis are being studied extensively to open new possibilities in drug development. One of which is the aspartate metabolism pathway. This amino acid pathway is proven to be pivotal for the survival of M. tuberculosis both in vitro and in vivo. Furthermore, this pathway also is absent in humans, making it a very promising candidate for further research and development in drug discovery. However, inhibitors against this pathway are not yet available as most suggested inhibitors against the various enzymes within this pathway only made it until the in-silico stage while few studies managed to synthesize their suggested inhibitors and had tested its anti-tuberculosis activity. This review will discuss said attempts in suggesting inhibitors against the critical enzymes that work within this pathway. The inhibitors that are reviewed in this paper are both synthetic and derived from natural products. The multitude of inhibitors proposed and the various enzymes that they are able to inhibit proved that this pathway has potential that is yet to be explored further.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
