Purine repressor

From Proteopedia

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].

Structure of E. coli purine processor complex with DNA and guanine (PDB entry 1wet)

Drag the structure with the mouse to rotate

3D structures of purine repressor

Updated on 08-February-2022

Purine repressor

Purine repressor complex with DNA and nucleotide

References

↑ 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