Glycineamide ribonucleotide explained

Glycineamide ribonucleotide (or GAR) is a biochemical intermediate in the formation of purine nucleotides via inosine-5-monophosphate, and hence is a building block for DNA and RNA.^{[1] [2] [3]} The vitamins thiamine^[4] and cobalamin^[5] also contain fragments derived from GAR.^[6]

GAR is the product of the enzyme phosphoribosylamine—glycine ligase acting on phosphoribosylamine (PRA) to combine it with glycine in a process driven by ATP. The reaction, forms an amide bond:^[7]

+ + ATP → + ADP + Pi

The biosynthesis pathway next adds a formyl group from 10-formyltetrahydrofolate to GAR, catalysed by phosphoribosylglycinamide formyltransferase in reaction and producing formylglycinamide ribotide (FGAR):^[8]

GAR + 10-formyltetrahydrofolate → FGAR + tetrahydrofolate

See also

• 5-Aminoimidazole ribotide
• Purine metabolism

Notes and References

1. Web site: Pathway: 5-aminoimidazole ribonucleotide biosynthesis I . R. Caspi . MetaCyc Metabolic Pathway Database . 2009-01-13 . 2022-02-02 .
2. 10.1007/s00018-008-8295-8 . Zhang . Y. . Morar . M. . Ealick . S.E. . Structural biology of the purine biosynthetic pathway . Cellular and Molecular Life Sciences . 65 . 3699–3724 . 2008 . 18712276 . 2596281 .
3. Book: 10.1007/978-981-16-0723-3_19 . Nucleotide Biosynthesis and Regulation . Fundamentals of Bacterial Physiology and Metabolism . 2021 . Gupta . Rani . Gupta . Namita . 525–554 . 978-981-16-0722-6 . 234897784 .
4. 10.1002/anie.201003419 . A "Radical Dance" in Thiamin Biosynthesis: Mechanistic Analysis of the Bacterial Hydroxymethylpyrimidine Phosphate Synthase . 2010 . Chatterjee . Abhishek . Hazra . Amrita B. . Abdelwahed . Sameh . Hilmey . David G. . Begley . Tadhg P. . Angewandte Chemie International Edition . 49 . 46 . 8653–8656 . 20886485 . 3147014 .
5. Web site: Pathway: 5-hydroxybenzimidazole biosynthesis (anaerobic) . R. Caspi . MetaCyc Metabolic Pathway Database . 2019-09-23 . 2022-02-10 .
6. 10.1021/jacs.5b03576 . Anaerobic 5-Hydroxybenzimidazole Formation from Aminoimidazole Ribotide: An Unanticipated Intersection of Thiamin and Vitamin B12 Biosynthesis . 2015 . Mehta . Angad P. . Abdelwahed . Sameh H. . Fenwick . Michael K. . Hazra . Amrita B. . Taga . Michiko E. . Zhang . Yang . Ealick . Steven E. . Begley . Tadhg P. . Journal of the American Chemical Society . 137 . 33 . 10444–10447 . 26237670 . 4753784 .
7. 10.1093/nar/gkq595 . Structural studies of tri-functional human GART . 2010 . Welin . Martin . Grossmann . Jörg Günter . Flodin . Susanne . Nyman . Tomas . Stenmark . Pål . Trésaugues . Lionel . Kotenyova . Tetyana . Johansson . Ida . Nordlund . Pär . Lehtiö . Lari . Nucleic Acids Research . 38 . 20 . 7308–7319 . 20631005 . 2978367 .
8. 10.1093/nar/gkq595 . Structural studies of tri-functional human GART . 2010 . Welin . Martin . Grossmann . Jörg Günter . Flodin . Susanne . Nyman . Tomas . Stenmark . Pål . Trésaugues . Lionel . Kotenyova . Tetyana . Johansson . Ida . Nordlund . Pär . Lehtiö . Lari . Nucleic Acids Research . 38 . 20 . 7308–7319 . 20631005 . 2978367 .