| Function
Purine repressor (PurR) is a member of the lac repressor family. PurP binds DNA via a highly conserved helix-turn-helix at the N terminal (DBD). PurP contains a nucleotide co-repressor binding domain as well (CBD). PurP binds to a 16-bp operator sequence and co-regulates genes which are involved in the biosynthesis of purine and pyrimidine nucleotides[1].
Structural highlights
The PurP guanine co-repressor binding site includes stacking interactions as well as hydrogen bonded ones. Water molecules are shown as red spheres. The DNA binding domain contains a helix-turn-helix-loop-helix motif which interacts with the DNA major groove and a hinge helix binding to to the DNA minor groove. Residue L54 interdigitates with the DNA central base pair[2].
- ↑ Wilson HR, Turnbough CL Jr. Role of the purine repressor in the regulation of pyrimidine gene expression in Escherichia coli K-12. J Bacteriol. 1990 Jun;172(6):3208-13. PMID:1971621
- ↑ Schumacher MA, Glasfeld A, Zalkin H, Brennan RG. The X-ray structure of the PurR-guanine-purF operator complex reveals the contributions of complementary electrostatic surfaces and a water-mediated hydrogen bond to corepressor specificity and binding affinity. J Biol Chem. 1997 Sep 5;272(36):22648-53. PMID:9278422
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3D structures of purine repressor
Updated on 20-August-2026
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- Purine repressor
- 1pru, 1prv - EcPurR DBD – Escherichia coli - NMR
- 1dbq - EcPurR CBD + Mg - NMR
- 1jhz - EcPurR CBD (mutant) + Mg
- 1o57 - BsPurR - Bacillus subtilis
- Purine repressor complex with DNA and nucleotide
- 1bdi, 1pnr, 1qp0, 1qp4, 1qpz, 1qqb - EcPurR + DNA + hypoxanthine
- 1bdh, 1jfs, 1jft, 1jh9, 1qp7, 1qqa, 1vpw, 2pud, 2pug - EcPurR (mutant) + DNA + hypoxanthine
- 1wet - EcPurR + DNA + guanine
- 2pua - EcPurR (mutant) + DNA + methylpurine
- 2pub, 2pue - EcPurR (mutant) + DNA + adenine
- 2puc, 2puf - EcPurR (mutant) + DNA + guanine
- 1zay - EcPurR + DNA + hypoxanthine + di-imino-purine
- 7rmw – BsPurR + PPGPP
References
