Disease relevance of SHMT

• This overexpression of eukaryotic tetrameric SHMT in E. coli and the purification and characterization of the recombinant enzyme should thus allow studies on the role of specific amino acids and domains in the activity of the enzyme [1].

High impact information on SHMT

• H134N SHMT was obtained in a dimeric form with only 6% of bound pyridoxal 5'-phosphate (PLP) compared with the wild type enzyme [2].
• In an attempt to unravel the role of conserved histidine residues in the structure-function of sheep liver cytosolic serine hydroxymethyltransferase (SHMT), three site-specific mutants (H134N, H147N, and H150N) were constructed and expressed [2].
• 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 [3].
• 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 [3].
• Identification of amino acid residues, essential for maintaining the tetrameric structure of sheep liver cytosolic serine hydroxymethyltransferase, by targeted mutagenesis [3].

Biological context of SHMT

• The full-length cDNA of SHMT was placed under the control of T7 promoter in pET-3C plasmid and expressed in Escherichia coli [1].
• A sheep liver cDNA clone for the cytosolic serine hydroxymethyltransferase (SHMT) was isolated and its nucleotide sequence determined [1].
• Mitochondrial SHMT was stable throughout gestation and with low constant mSHMT RNA levels [4].
• It is obvious that SHMT plays an indispensable role in nucleic acid biosynthesis; therefore, designing and developing a repressor/inhibitor of the SHMT gene/protein may resolve the problem of drug resistance to cancer chemotherapy [5].
• The complete amino-acid sequence of sheep liver cytosolic serine hydroxymethyltransferase was determined from an analysis of tryptic, chymotryptic, CNBr and hydroxylamine peptides [6].

Anatomical context of SHMT

• These data suggest that flux through SHMT and GCS accounts for 50% of serine biosynthesis in mid-gestation fetal ovine hepatocytes [7].

Associations of SHMT with chemical compounds

• The apoenzyme obtained upon removal of the cofactor was inactive and could be reconstituted by the addition of pyridoxal 5'-phosphate demonstrating that the recombinant SHMT was functionally very similar to the native SHMT [1].
• Serine hydroxymethyltransferase (SHMT) catalyzes the reversible cleavage of serine to form glycine and single carbon groups that are essential for many biosynthetic pathways [8].
• In an attempt to unravel the role of a conserved aspartate (D89) in sheep-liver tetrameric serine hydroxymethyltransferase (SHMT), it was converted into aspargine by site-directed mutagenesis [9].
• The results demonstrate clearly that the dimer is an intermediate in the urea-induced equilibrium unfolding/refolding of sheep liver SHMT; and PLP, in addition to its role in catalysis, is required for the stabilization of the tetrameric structure of the enzyme [10].
• Serine hydroxymethyltransferase (SHMT), a pyridoxal-5' -phosphate (PLP) dependent enzyme catalyzes the interconversion of L-Ser and Gly using tetrahydrofolate as a substrate [11].

Analytical, diagnostic and therapeutic context of SHMT

• The mechanism of interaction of O-amino-D-serine (OADS) with sheep liver serine hydroxymethyltransferase (EC 2.1.2.1) (SHMT) was established by measuring changes in the enzyme activity, absorption spectra, circular dichroism (CD) spectra, and stopped-flow spectrophotometry [12].
• Size exclusion chromatography showed that the tetrameric SHMT unfolds via the intermediate formation of dimers [10].
• The gene encoding for SHMT was amplified by PCR from genomic DNA of Bacillus stearothermophilus and the PCR product was cloned and overexpressed in Escherichia coli [11].

References