Cloning and characterization of a new purine biosynthetic enzyme: a non-folate glycinamide ribonucleotide transformylase from E. coli.
A novel GAR transformylase has been isolated and characterized from E. coli. The protein, a product of the purT gene, is a monomer of molecular weight 42 kDa and catalyzes the production of beta-formyl GAR from formate, ATP, and beta-GAR. As such it is an alternative to the formyl-folate utilizing purN GAR transformylase. No significant homology exists between the two transformylases. However, the purT protein shows significant homology to the purK protein, also involved in purine biosynthesis. Two different purT reactions have been characterized: one producing fGAR from ATP, beta-GAR, and formate and the other producing acetyl phosphate and ADP from acetate and ATP. The purT GAR transformylase is the first unknown de novo purine biosynthetic enzyme to be discovered in the last 30 years and represents another step forward in understanding cellular control of purine levels.
Marolewski
A
A
Department of Chemistry, Pennsylvania State University, University Park 16802.
Smith
J M
JM
Benkovic
S J
SJ
D000217:Acyltransferases / Q000235:genetics* / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000378:metabolism; D000595:Amino Acid Sequence; D001483:Base Sequence; D003001:Cloning, Molecular; D004269:DNA, Bacterial / Q000235:genetics; D004926:Escherichia coli / Q000201:enzymology*; D029968:Escherichia coli Proteins; D005561:Formates / Q000378:metabolism; D005798:Genes, Bacterial; D019877:Hydroxymethyl and Formyl Transferases; D007700:Kinetics; D008969:Molecular Sequence Data; D008970:Molecular Weight; D051026:Phosphoribosylglycinamide Formyltransferase; D013379:Substrate Specificity
D004269:DNA, Bacterial; D029968:Escherichia coli Proteins; D005561:Formates; D000255:Adenosine Triphosphate; D019877:Hydroxymethyl and Formyl Transferases; C494825:purT protein, E coli; D051026:Phosphoribosylglycinamide Formyltransferase; D000217:Acyltransferases