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Location of the pteroylpolyglutamate-binding site on rabbit cytosolic serine hydroxymethyltransferase.
J Biol Chem. 2003 Jan 24; 278(4):2645-53.JB

Abstract

Serine hydroxymethyltransferase (SHMT; EC 2.1.2.1) catalyzes the reversible interconversion of serine and glycine with transfer of the serine side chain one-carbon group to tetrahydropteroylglutamate (H(4)PteGlu), and also the conversion of 5,10-methenyl-H(4)PteGlu to 5-formyl-H(4)PteGlu. In the cell, H(4)PteGlu carries a poly-gamma-glutamyl tail of at least 3 glutamyl residues that is required for physiological activity. This study combines solution binding and mutagenesis studies with crystallographic structure determination to identify the extended binding site for tetrahydropteroylpolyglutamate on rabbit cytosolic SHMT. Equilibrium binding and kinetic measurements of H(4)PteGlu(3) and H(4)PteGlu(5) with wild-type and Lys --> Gln or Glu site mutant homotetrameric rabbit cytosolic SHMTs identified lysine residues that contribute to the binding of the polyglutamate tail. The crystal structure of the enzyme in complex with 5-formyl-H(4)PteGlu(3) confirms the solution data and indicates that the conformation of the pteridine ring and its interactions with the enzyme differ slightly from those observed in complexes of the monoglutamate cofactor. The polyglutamate chain, which does not contribute to catalysis, exists in multiple conformations in each of the two occupied binding sites and appears to be bound by the electrostatic field created by the cationic residues, with only limited interactions with specific individual residues.

Authors+Show Affiliations

Department of Biochemistry and the Institute for Structural Biology and Drug Discovery, Virginia Commonwealth University, Richmond 23219-1570, USA.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, U.S. Gov't, P.H.S.

Language

eng

PubMed ID

12438316

Citation

Fu, Tzu-Fun, et al. "Location of the Pteroylpolyglutamate-binding Site On Rabbit Cytosolic Serine Hydroxymethyltransferase." The Journal of Biological Chemistry, vol. 278, no. 4, 2003, pp. 2645-53.
Fu TF, Scarsdale JN, Kazanina G, et al. Location of the pteroylpolyglutamate-binding site on rabbit cytosolic serine hydroxymethyltransferase. J Biol Chem. 2003;278(4):2645-53.
Fu, T. F., Scarsdale, J. N., Kazanina, G., Schirch, V., & Wright, H. T. (2003). Location of the pteroylpolyglutamate-binding site on rabbit cytosolic serine hydroxymethyltransferase. The Journal of Biological Chemistry, 278(4), 2645-53.
Fu TF, et al. Location of the Pteroylpolyglutamate-binding Site On Rabbit Cytosolic Serine Hydroxymethyltransferase. J Biol Chem. 2003 Jan 24;278(4):2645-53. PubMed PMID: 12438316.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Location of the pteroylpolyglutamate-binding site on rabbit cytosolic serine hydroxymethyltransferase. AU - Fu,Tzu-Fun, AU - Scarsdale,J Neel, AU - Kazanina,Galina, AU - Schirch,Verne, AU - Wright,H Tonie, Y1 - 2002/11/15/ PY - 2002/11/20/pubmed PY - 2003/3/5/medline PY - 2002/11/20/entrez SP - 2645 EP - 53 JF - The Journal of biological chemistry JO - J Biol Chem VL - 278 IS - 4 N2 - Serine hydroxymethyltransferase (SHMT; EC 2.1.2.1) catalyzes the reversible interconversion of serine and glycine with transfer of the serine side chain one-carbon group to tetrahydropteroylglutamate (H(4)PteGlu), and also the conversion of 5,10-methenyl-H(4)PteGlu to 5-formyl-H(4)PteGlu. In the cell, H(4)PteGlu carries a poly-gamma-glutamyl tail of at least 3 glutamyl residues that is required for physiological activity. This study combines solution binding and mutagenesis studies with crystallographic structure determination to identify the extended binding site for tetrahydropteroylpolyglutamate on rabbit cytosolic SHMT. Equilibrium binding and kinetic measurements of H(4)PteGlu(3) and H(4)PteGlu(5) with wild-type and Lys --> Gln or Glu site mutant homotetrameric rabbit cytosolic SHMTs identified lysine residues that contribute to the binding of the polyglutamate tail. The crystal structure of the enzyme in complex with 5-formyl-H(4)PteGlu(3) confirms the solution data and indicates that the conformation of the pteridine ring and its interactions with the enzyme differ slightly from those observed in complexes of the monoglutamate cofactor. The polyglutamate chain, which does not contribute to catalysis, exists in multiple conformations in each of the two occupied binding sites and appears to be bound by the electrostatic field created by the cationic residues, with only limited interactions with specific individual residues. SN - 0021-9258 UR - https://www.unboundmedicine.com/medline/citation/12438316/Location_of_the_pteroylpolyglutamate_binding_site_on_rabbit_cytosolic_serine_hydroxymethyltransferase_ DB - PRIME DP - Unbound Medicine ER -