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Identification of amino acid residues, essential for maintaining the tetrameric structure of sheep liver cytosolic serine hydroxymethyltransferase, by targeted mutagenesis.
Biochem J. 2003 Feb 01; 369(Pt 3):469-76.BJ

Abstract

Serine hydroxymethyltransferase (SHMT), a pyridoxal 5'-phosphate (PLP)-dependent enzyme, catalyses the transfer of the hydroxymethyl group from serine to tetrahydrofolate to yield glycine and N (5), N (10)-methylenetetrahydrofolate. An analysis of the known SHMT sequences indicated that several amino acid residues were conserved. In this paper, we report the identification of the amino acid residues essential for maintaining the oligomeric structure of sheep liver cytosolic recombinant SHMT (scSHMT) through intra- and inter-subunit interactions and by stabilizing the binding of PLP at the active site. The mutation of Lys-71, Arg-80 and Asp-89, the residues involved in intra-subunit ionic interactions, disturbed the oligomeric structure and caused a loss of catalytic activity. Mutation of Trp-110 to Phe was without effect, while its mutation to Ala resulted in the enzyme being present in the insoluble fraction. These results suggested that Trp-110 located in a cluster of hydrophobic residues was essential for proper folding of the enzyme. Arg-98 and His-304, residues involved in the inter-subunit interactions, were essential for maintaining the tetrameric structure. Mutation of Tyr-72, Asp-227 and His-356 at the active site which interact with PLP resulted in the loss of PLP, and hence loss of tetrameric structure. Mutation of Cys-203, located away from the active site, weakened PLP binding indirectly. The results demonstrate that in addition to residues involved in inter-subunit interactions, those involved in PLP binding and intra-subunit interactions also affect the oligomeric structure of scSHMT.

Authors+Show Affiliations

Department of Biochemistry, Indian Institute of Science, Bangalore-560 012, India.No affiliation info availableNo affiliation info available

Pub Type(s)

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

Language

eng

PubMed ID

12392447

Citation

Jala, Venkatakrishna Rao, et al. "Identification of Amino Acid Residues, Essential for Maintaining the Tetrameric Structure of Sheep Liver Cytosolic Serine Hydroxymethyltransferase, By Targeted Mutagenesis." The Biochemical Journal, vol. 369, no. Pt 3, 2003, pp. 469-76.
Jala VR, Appaji Rao N, Savithri HS. Identification of amino acid residues, essential for maintaining the tetrameric structure of sheep liver cytosolic serine hydroxymethyltransferase, by targeted mutagenesis. Biochem J. 2003;369(Pt 3):469-76.
Jala, V. R., Appaji Rao, N., & Savithri, H. S. (2003). Identification of amino acid residues, essential for maintaining the tetrameric structure of sheep liver cytosolic serine hydroxymethyltransferase, by targeted mutagenesis. The Biochemical Journal, 369(Pt 3), 469-76.
Jala VR, Appaji Rao N, Savithri HS. Identification of Amino Acid Residues, Essential for Maintaining the Tetrameric Structure of Sheep Liver Cytosolic Serine Hydroxymethyltransferase, By Targeted Mutagenesis. Biochem J. 2003 Feb 1;369(Pt 3):469-76. PubMed PMID: 12392447.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Identification of amino acid residues, essential for maintaining the tetrameric structure of sheep liver cytosolic serine hydroxymethyltransferase, by targeted mutagenesis. AU - Jala,Venkatakrishna Rao, AU - Appaji Rao,Naropantul, AU - Savithri,Handanahal Subbarao, PY - 2002/10/22/accepted PY - 2002/10/04/revised PY - 2002/07/23/received PY - 2002/10/24/pubmed PY - 2003/3/19/medline PY - 2002/10/24/entrez SP - 469 EP - 76 JF - The Biochemical journal JO - Biochem. J. VL - 369 IS - Pt 3 N2 - Serine hydroxymethyltransferase (SHMT), a pyridoxal 5'-phosphate (PLP)-dependent enzyme, catalyses the transfer of the hydroxymethyl group from serine to tetrahydrofolate to yield glycine and N (5), N (10)-methylenetetrahydrofolate. An analysis of the known SHMT sequences indicated that several amino acid residues were conserved. In this paper, we report the identification of the amino acid residues essential for maintaining the oligomeric structure of sheep liver cytosolic recombinant SHMT (scSHMT) through intra- and inter-subunit interactions and by stabilizing the binding of PLP at the active site. The mutation of Lys-71, Arg-80 and Asp-89, the residues involved in intra-subunit ionic interactions, disturbed the oligomeric structure and caused a loss of catalytic activity. Mutation of Trp-110 to Phe was without effect, while its mutation to Ala resulted in the enzyme being present in the insoluble fraction. These results suggested that Trp-110 located in a cluster of hydrophobic residues was essential for proper folding of the enzyme. Arg-98 and His-304, residues involved in the inter-subunit interactions, were essential for maintaining the tetrameric structure. Mutation of Tyr-72, Asp-227 and His-356 at the active site which interact with PLP resulted in the loss of PLP, and hence loss of tetrameric structure. Mutation of Cys-203, located away from the active site, weakened PLP binding indirectly. The results demonstrate that in addition to residues involved in inter-subunit interactions, those involved in PLP binding and intra-subunit interactions also affect the oligomeric structure of scSHMT. SN - 0264-6021 UR - https://www.unboundmedicine.com/medline/citation/12392447/Identification_of_amino_acid_residues_essential_for_maintaining_the_tetrameric_structure_of_sheep_liver_cytosolic_serine_hydroxymethyltransferase_by_targeted_mutagenesis_ L2 - https://portlandpress.com/biochemj/article-lookup/doi/10.1042/BJ20021160 DB - PRIME DP - Unbound Medicine ER -