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Catalytic and ligand-binding characteristics of Plasmodium falciparum serine hydroxymethyltransferase.
Mol Biochem Parasitol. 2009 Nov; 168(1):74-83.MB

Abstract

The plant-like, bifunctional dihydrofolate reductase-thymidylate synthase (DHFR-TS) from malaria parasites has been a good target for drug development. Dihydrofolate reductase (DHFR) is inhibited by clinically established antimalarials, pyrimethamine and cycloguanil. Thymidylate synthase (TS) is the target of potent experimental antimalarials such as 5-fluoroorotate and 1843U89. Another enzyme in folate recycling, serine hydroxymethyltransferase (SHMT), produces 5,10-methylenetetrahydrofolate which, in many cells, is required for the de novo, biosynthesis of thymidine and methionine. Thus, the biochemical characterization of malarial SHMT was of interest. The principle, active Plasmodium falciparum SHMT (PfSHMT) was expressed in E. coli and purified using an N-terminal histidine tag. Unlike the plant enzyme, but like the host enzyme, PfSHMT requires the cofactor pyridoxal 5'-phosphate for enzymatic activity. The substrate specificities for serine, tetrahydrofolate, and pyridoxal 5'-phosphate were comparable to those for SHMT from other organisms. Antifolates developed for DHFR and TS inhibited SHMT in the mid-micromolar range, offering insights into the binding preferences of SHMT but clearly leaving room for improved new inhibitors. As previously seen with P. falciparum DHFR-TS, PfSHMT bound its cognate mRNA but not control RNA for actin. RNA binding was not reversed with enzyme substrates. Unlike DHFR-TS, the SHMT RNA-protein interaction was not tight enough to inhibit translation. Another gene PF14_0534, previously proposed to code for an alternate mitochondrial SHMT, was also expressed in E. coli but found to be inactive. This protein, nor DHFR-TS, enhanced the catalytic activity of PfSHMT. The present results set the stage for developing specific, potent inhibitors of SHMT from P. falciparum.

Authors+Show Affiliations

Department of Chemistry, University of Washington, Seattle, WA 98195, USA.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, N.I.H., Extramural
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

19591883

Citation

Pang, Cullen K T., et al. "Catalytic and Ligand-binding Characteristics of Plasmodium Falciparum Serine Hydroxymethyltransferase." Molecular and Biochemical Parasitology, vol. 168, no. 1, 2009, pp. 74-83.
Pang CK, Hunter JH, Gujjar R, et al. Catalytic and ligand-binding characteristics of Plasmodium falciparum serine hydroxymethyltransferase. Mol Biochem Parasitol. 2009;168(1):74-83.
Pang, C. K., Hunter, J. H., Gujjar, R., Podutoori, R., Bowman, J., Mudeppa, D. G., & Rathod, P. K. (2009). Catalytic and ligand-binding characteristics of Plasmodium falciparum serine hydroxymethyltransferase. Molecular and Biochemical Parasitology, 168(1), 74-83. https://doi.org/10.1016/j.molbiopara.2009.06.011
Pang CK, et al. Catalytic and Ligand-binding Characteristics of Plasmodium Falciparum Serine Hydroxymethyltransferase. Mol Biochem Parasitol. 2009;168(1):74-83. PubMed PMID: 19591883.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Catalytic and ligand-binding characteristics of Plasmodium falciparum serine hydroxymethyltransferase. AU - Pang,Cullen K T, AU - Hunter,Joshua H, AU - Gujjar,Ramesh, AU - Podutoori,Ramulu, AU - Bowman,Julie, AU - Mudeppa,Devaraja G, AU - Rathod,Pradipsinh K, Y1 - 2009/07/08/ PY - 2009/04/17/received PY - 2009/05/29/revised PY - 2009/06/25/accepted PY - 2009/7/14/entrez PY - 2009/7/14/pubmed PY - 2009/10/17/medline SP - 74 EP - 83 JF - Molecular and biochemical parasitology JO - Mol Biochem Parasitol VL - 168 IS - 1 N2 - The plant-like, bifunctional dihydrofolate reductase-thymidylate synthase (DHFR-TS) from malaria parasites has been a good target for drug development. Dihydrofolate reductase (DHFR) is inhibited by clinically established antimalarials, pyrimethamine and cycloguanil. Thymidylate synthase (TS) is the target of potent experimental antimalarials such as 5-fluoroorotate and 1843U89. Another enzyme in folate recycling, serine hydroxymethyltransferase (SHMT), produces 5,10-methylenetetrahydrofolate which, in many cells, is required for the de novo, biosynthesis of thymidine and methionine. Thus, the biochemical characterization of malarial SHMT was of interest. The principle, active Plasmodium falciparum SHMT (PfSHMT) was expressed in E. coli and purified using an N-terminal histidine tag. Unlike the plant enzyme, but like the host enzyme, PfSHMT requires the cofactor pyridoxal 5'-phosphate for enzymatic activity. The substrate specificities for serine, tetrahydrofolate, and pyridoxal 5'-phosphate were comparable to those for SHMT from other organisms. Antifolates developed for DHFR and TS inhibited SHMT in the mid-micromolar range, offering insights into the binding preferences of SHMT but clearly leaving room for improved new inhibitors. As previously seen with P. falciparum DHFR-TS, PfSHMT bound its cognate mRNA but not control RNA for actin. RNA binding was not reversed with enzyme substrates. Unlike DHFR-TS, the SHMT RNA-protein interaction was not tight enough to inhibit translation. Another gene PF14_0534, previously proposed to code for an alternate mitochondrial SHMT, was also expressed in E. coli but found to be inactive. This protein, nor DHFR-TS, enhanced the catalytic activity of PfSHMT. The present results set the stage for developing specific, potent inhibitors of SHMT from P. falciparum. SN - 1872-9428 UR - https://www.unboundmedicine.com/medline/citation/19591883/Catalytic_and_ligand_binding_characteristics_of_Plasmodium_falciparum_serine_hydroxymethyltransferase_ L2 - https://linkinghub.elsevier.com/retrieve/pii/S0166-6851(09)00184-4 DB - PRIME DP - Unbound Medicine ER -