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Serine hydroxymethyltransferase from Plasmodium vivax is different in substrate specificity from its homologues.
FEBS J. 2009 Aug; 276(15):4023-36.FJ

Abstract

The putative gene of Plasmodium vivax serine hydroxymethyltransferase (PvSHMT; EC 2.1.2.1) was cloned and expressed in Escherichia coli. The purified enzyme was shown to be a dimeric protein with a monomeric molecular mass of 49 kDa. PvSHMT has a maximum absorption peak at 422 nm with a molar absorption coefficient of 6370 M(-1) x cm(-1). The K(d) for binding of the enzyme and pyridoxal-5-phosphate was 0.14 +/- 0.01 microM. An alternative assay for measuring the tetrahydrofolate-dependent SHMT activity based on the coupled reaction with 5,10-methylenetetrahydrofolate reductase (EC 1.5.1.20) from E. coli was developed. PvSHMT uses a ternary-complex mechanism with a k(cat) value of 0.98 +/- 0.06 s(-1) and K(m) values of 0.18 +/- 0.03 and 0.14 +/- 0.02 mM for L-serine and tetrahydrofolate, respectively. The optimum pH of the SHMT reaction was 8.0 and an Arrhenius's plot showed a transition temperature of 19 degrees C. Besides L-serine, PvSHMT forms an external aldimine complex with D-serine, L-alanine, L-threonine and glycine. PvSHMT also catalyzes the tetrahydrofolate-independent retro-aldol cleavage of 3-hydroxy amino acids. Although L-serine is a physiological substrate for SHMT in the tetrahydrofolate-dependent reaction, PvSHMT can also use D-serine. In the absence of tetrahydrofolate at high pH, PvSHMT forms an enzyme-quinonoid complex with D-serine, but not with L-serine, whereas SHMT from rabbit liver was reported to form an enzyme-quinonoid complex with L-serine. The substrate specificity difference between PvSHMT and the mammalian enzyme indicates the dissimilarity between their active sites, which could be exploited for the development of specific inhibitors against PvSHMT.

Authors+Show Affiliations

Department of Biochemistry and Center for Excellence in Protein Structure and Function, Faculty of Science, Mahidol University, Bangkok, Thailand.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

19549189

Citation

Sopitthummakhun, Kittipat, et al. "Serine Hydroxymethyltransferase From Plasmodium Vivax Is Different in Substrate Specificity From Its Homologues." The FEBS Journal, vol. 276, no. 15, 2009, pp. 4023-36.
Sopitthummakhun K, Maenpuen S, Yuthavong Y, et al. Serine hydroxymethyltransferase from Plasmodium vivax is different in substrate specificity from its homologues. FEBS J. 2009;276(15):4023-36.
Sopitthummakhun, K., Maenpuen, S., Yuthavong, Y., Leartsakulpanich, U., & Chaiyen, P. (2009). Serine hydroxymethyltransferase from Plasmodium vivax is different in substrate specificity from its homologues. The FEBS Journal, 276(15), 4023-36. https://doi.org/10.1111/j.1742-4658.2009.07111.x
Sopitthummakhun K, et al. Serine Hydroxymethyltransferase From Plasmodium Vivax Is Different in Substrate Specificity From Its Homologues. FEBS J. 2009;276(15):4023-36. PubMed PMID: 19549189.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Serine hydroxymethyltransferase from Plasmodium vivax is different in substrate specificity from its homologues. AU - Sopitthummakhun,Kittipat, AU - Maenpuen,Somchart, AU - Yuthavong,Yongyuth, AU - Leartsakulpanich,Ubolsree, AU - Chaiyen,Pimchai, Y1 - 2009/06/22/ PY - 2009/6/25/entrez PY - 2009/6/25/pubmed PY - 2009/9/17/medline SP - 4023 EP - 36 JF - The FEBS journal JO - FEBS J. VL - 276 IS - 15 N2 - The putative gene of Plasmodium vivax serine hydroxymethyltransferase (PvSHMT; EC 2.1.2.1) was cloned and expressed in Escherichia coli. The purified enzyme was shown to be a dimeric protein with a monomeric molecular mass of 49 kDa. PvSHMT has a maximum absorption peak at 422 nm with a molar absorption coefficient of 6370 M(-1) x cm(-1). The K(d) for binding of the enzyme and pyridoxal-5-phosphate was 0.14 +/- 0.01 microM. An alternative assay for measuring the tetrahydrofolate-dependent SHMT activity based on the coupled reaction with 5,10-methylenetetrahydrofolate reductase (EC 1.5.1.20) from E. coli was developed. PvSHMT uses a ternary-complex mechanism with a k(cat) value of 0.98 +/- 0.06 s(-1) and K(m) values of 0.18 +/- 0.03 and 0.14 +/- 0.02 mM for L-serine and tetrahydrofolate, respectively. The optimum pH of the SHMT reaction was 8.0 and an Arrhenius's plot showed a transition temperature of 19 degrees C. Besides L-serine, PvSHMT forms an external aldimine complex with D-serine, L-alanine, L-threonine and glycine. PvSHMT also catalyzes the tetrahydrofolate-independent retro-aldol cleavage of 3-hydroxy amino acids. Although L-serine is a physiological substrate for SHMT in the tetrahydrofolate-dependent reaction, PvSHMT can also use D-serine. In the absence of tetrahydrofolate at high pH, PvSHMT forms an enzyme-quinonoid complex with D-serine, but not with L-serine, whereas SHMT from rabbit liver was reported to form an enzyme-quinonoid complex with L-serine. The substrate specificity difference between PvSHMT and the mammalian enzyme indicates the dissimilarity between their active sites, which could be exploited for the development of specific inhibitors against PvSHMT. SN - 1742-4658 UR - https://www.unboundmedicine.com/medline/citation/19549189/Serine_hydroxymethyltransferase_from_Plasmodium_vivax_is_different_in_substrate_specificity_from_its_homologues_ L2 - https://doi.org/10.1111/j.1742-4658.2009.07111.x DB - PRIME DP - Unbound Medicine ER -