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EC Number

Catalytic Site Atlas

CSA LITERATURE entry for 1dfo

E.C. nameglycine hydroxymethyltransferase
SpeciesEscherichia coli (Bacteria)
E.C. Number (IntEnz)
CSA Homologues of 1dfoThere are 51 Homologs
CSA Entries With UniProtID P0A825
CSA Entries With EC Number
PDBe Entry 1dfo
PDBSum Entry 1dfo
MACiE Entry 1dfo

Literature Report

IntroductionSerine hydroxymethyltransferase (SHMT) catalyses the reversible interconversion of serine and glycine with tetrahydrofolate serving as the one-carbon carrier. This reaction serves as the major source of one-carbon groups required for the biosynthesis of purines, thymidylate, methionine and many neurotransmitters.
MechansimThe THF-dependent reaction is thought to proceed via a retroaldol mechanism. The serine substrate first forms the external aldimine by displacing Lys229 from the internal aldimine. Glu57 abstracts the C3-OH proton, initiating the loss of formaldehyde from the intermediate leaving behind the glycine-quinoid aldimine. This rearranges to form the glycine aldimine. This intermediate is broken down by nucleophilic attack of Lys229 at the imine functionality, displacing glycine and reforming the internal aldimine, the enzyme resting state. The released formaldehyde reacts with the THF cofactor to form 5,10-methylene-H4-folate.

Catalytic Sites for 1dfo

Literature References

Notes:Residues involved in proton relay have not yet been identified.
Szebenyi DM
Serine hydroxymethyltransferase: role of glu75 and evidence that serine is cleaved by a retroaldol mechanism.
Biochemistry 2004 43 6865-6876
PubMed: 15170323
Schirch V
Serine hydroxymethyltransferase revisited.
Curr Opin Chem Biol 2005 9 482-487
PubMed: 16125438
Trivedi V
Crystal structure of binary and ternary complexes of serine hydroxymethyltransferase from Bacillus stearothermophilus: insights into the catalytic mechanism.
J Biol Chem 2002 277 17161-17169
PubMed: 11877399