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Human and Plasmodium serine hydroxymethyltransferases differ in rate-limiting steps and pH-dependent substrate inhibition behavior.
Arch Biochem Biophys. 2017 09 15; 630:91-100.AB

Abstract

Serine hydroxymethyltransferase (SHMT), an essential enzyme for cell growth and development, catalyzes the transfer of -CH2OH from l-serine to tetrahydrofolate (THF) to form glycine and 5,10-methylenetetrahydrofolate (MTHF) which is used for nucleotide synthesis. Insights into the ligand binding and inhibition properties of human cytosolic SHMT (hcSHMT) and Plasmodium SHMT (PvSHMT) are crucial for designing specific drugs against malaria and cancer. The results presented here revealed strong and pH-dependent THF inhibition of hcSHMT. In contrast, in PvSHMT, THF inhibition and the influence of pH were not as pronounced. Ligand binding experiments performed at various pH values indicated that the hcSHMT:Gly complex binds THF more tightly at lower pH conditions, while the binding affinity of the PvSHMT:Gly complex for THF is not pH-dependent. Pre-steady state kinetic (rapid-quench) analysis of hcSHMT showed burst kinetics, indicating that glycine formation occurs fastest in the first turnover relative to the subsequent turnovers i.e. glycine release is the rate-limiting step in the hcSHMT reaction. All data suggest that excess THF likely binds E:Gly binary complex and forms the E:Gly:THF dead-end complex before glycine is released. A unique flap motif found in the structure of hcSHMT may be the key structural feature that imparts these described characteristics of hcSHMT.

Authors+Show Affiliations

Department of Biochemistry and Center for Excellence in Protein and Enzyme Technology, Faculty of Science, Mahidol University, Bangkok 10400, Thailand.Department of Biochemistry, Faculty of Science, Burapha University, Chonburi 20131, Thailand.National Center for Genetic Engineering and Biotechnology, National Science and Technology Development Agency, Pathumthani 12120, Thailand.National Center for Genetic Engineering and Biotechnology, National Science and Technology Development Agency, Pathumthani 12120, Thailand. Electronic address: ubolsree@biotec.or.th.Department of Biochemistry and Center for Excellence in Protein and Enzyme Technology, Faculty of Science, Mahidol University, Bangkok 10400, Thailand; Department of Biomolecular Science and Engineering, School of Biomolecular Science & Engineering, Vidyasirimedhi Institute of Science and Technology (VISTEC), Wangchan Valley, Rayong 21210, Thailand. Electronic address: pimchai.cha@mahidol.ac.th.

Pub Type(s)

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

Language

eng

PubMed ID

28760597

Citation

Amornwatcharapong, Watcharee, et al. "Human and Plasmodium Serine Hydroxymethyltransferases Differ in Rate-limiting Steps and pH-dependent Substrate Inhibition Behavior." Archives of Biochemistry and Biophysics, vol. 630, 2017, pp. 91-100.
Amornwatcharapong W, Maenpuen S, Chitnumsub P, et al. Human and Plasmodium serine hydroxymethyltransferases differ in rate-limiting steps and pH-dependent substrate inhibition behavior. Arch Biochem Biophys. 2017;630:91-100.
Amornwatcharapong, W., Maenpuen, S., Chitnumsub, P., Leartsakulpanich, U., & Chaiyen, P. (2017). Human and Plasmodium serine hydroxymethyltransferases differ in rate-limiting steps and pH-dependent substrate inhibition behavior. Archives of Biochemistry and Biophysics, 630, 91-100. https://doi.org/10.1016/j.abb.2017.07.017
Amornwatcharapong W, et al. Human and Plasmodium Serine Hydroxymethyltransferases Differ in Rate-limiting Steps and pH-dependent Substrate Inhibition Behavior. Arch Biochem Biophys. 2017 09 15;630:91-100. PubMed PMID: 28760597.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Human and Plasmodium serine hydroxymethyltransferases differ in rate-limiting steps and pH-dependent substrate inhibition behavior. AU - Amornwatcharapong,Watcharee, AU - Maenpuen,Somchart, AU - Chitnumsub,Penchit, AU - Leartsakulpanich,Ubolsree, AU - Chaiyen,Pimchai, Y1 - 2017/07/29/ PY - 2017/05/23/received PY - 2017/07/24/revised PY - 2017/07/27/accepted PY - 2017/8/2/pubmed PY - 2017/9/5/medline PY - 2017/8/2/entrez KW - Ligand binding KW - Pyridoxal 5′-phosphate KW - Rapid-quench flow KW - Rate determining step KW - Serine hydroxymethyltransferase KW - Substrate inhibition KW - Tetrahydrofolate SP - 91 EP - 100 JF - Archives of biochemistry and biophysics JO - Arch. Biochem. Biophys. VL - 630 N2 - Serine hydroxymethyltransferase (SHMT), an essential enzyme for cell growth and development, catalyzes the transfer of -CH2OH from l-serine to tetrahydrofolate (THF) to form glycine and 5,10-methylenetetrahydrofolate (MTHF) which is used for nucleotide synthesis. Insights into the ligand binding and inhibition properties of human cytosolic SHMT (hcSHMT) and Plasmodium SHMT (PvSHMT) are crucial for designing specific drugs against malaria and cancer. The results presented here revealed strong and pH-dependent THF inhibition of hcSHMT. In contrast, in PvSHMT, THF inhibition and the influence of pH were not as pronounced. Ligand binding experiments performed at various pH values indicated that the hcSHMT:Gly complex binds THF more tightly at lower pH conditions, while the binding affinity of the PvSHMT:Gly complex for THF is not pH-dependent. Pre-steady state kinetic (rapid-quench) analysis of hcSHMT showed burst kinetics, indicating that glycine formation occurs fastest in the first turnover relative to the subsequent turnovers i.e. glycine release is the rate-limiting step in the hcSHMT reaction. All data suggest that excess THF likely binds E:Gly binary complex and forms the E:Gly:THF dead-end complex before glycine is released. A unique flap motif found in the structure of hcSHMT may be the key structural feature that imparts these described characteristics of hcSHMT. SN - 1096-0384 UR - https://www.unboundmedicine.com/medline/citation/28760597/Human_and_Plasmodium_serine_hydroxymethyltransferases_differ_in_rate_limiting_steps_and_pH_dependent_substrate_inhibition_behavior_ L2 - https://linkinghub.elsevier.com/retrieve/pii/S0003-9861(17)30330-2 DB - PRIME DP - Unbound Medicine ER -