Structural highlights
1jft is a 2 chain structure with sequence from "bacillus_coli"_migula_1895 "bacillus coli" migula 1895. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
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| Ligands: | , |
| Related: | 1pnr, 1qpz, 1jfs, 1jh9, 1jhz |
| Gene: | PURR ("Bacillus coli" Migula 1895) |
| Resources: | FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT |
Function
[PURR_ECOLI] Is the main repressor of the genes involved in the de novo synthesis of purine nucleotides, regulating purB, purC, purEK, purF, purHD, purL, purMN and guaBA expression. In addition, it participates in the regulation or coregulation of genes involved in de novo pyrimidine nucleotide biosynthesis, salvage and uptake (pyrC, pyrD, carAB and codBA), and of several genes encoding enzymes necessary for nucleotide and polyamine biosynthesis (prsA, glyA, gcvTHP, speA, glnB). Binds to a 16-bp palindromic sequence located within the promoter region of pur regulon genes. The consensus binding sequence is 5'-ACGCAAACGTTTTCNT-3'. PurR is allosterically activated to bind its cognate DNA by binding the purine corepressors, hypoxanthine or guanine, thereby effecting transcription repression.[1] [2] [3] [4]
Evolutionary Conservation
Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf.
Publication Abstract from PubMed
The crystal structures of corepressor-bound and free Escherichia coli purine repressor (PurR) have delineated the roles of several residues in corepressor binding and specificity and the intramolecular signal transduction (allosterism) of this LacI/GalR family member. From these structures, residue W147 was implicated as a key component of the allosteric response, but in many members of the LacI/GalR family, position 147 is occupied by an arginine. To understand the role of this tryptophan at position 147, three proteins, substituted by phenylalanine (W147F), alanine (W147A), or arginine (W147R), were constructed and characterized in vivo and in vitro, and their structures were determined. W147F displays a decreased affinity for corepressor and is a poor repressor in vivo. W147A and W147R, on the other hand, are super repressors and bind corepressor 13.6 and 7.9 times more tightly, respectively, than wild-type. Each mutant PurR-hypoxanthine-purF operator holo complex crystallizes isomorphously to wild-type. Whereas the apo corepressor binding domain (CBD) of W147F crystallizes under those conditions used for the wild-type protein, neither the apo CBD of W147R nor W147A crystallizes, although screened extensively for new crystal forms. Structures of the holo repressor mutants have been solved to resolutions between 2.5 and 2.9 A, and the structure of the apo CBD of W147F has been solved to 2.4 A resolution. These structures provide insight into the altered biochemical properties and physiological functions of these mutants, which appear to depend on the sometimes subtle preference for one conformation (apo vs holo) over the other.
Role of residue 147 in the gene regulatory function of the Escherichia coli purine repressor.,Huffman JL, Lu F, Zalkin H, Brennan RG Biochemistry. 2002 Jan 15;41(2):511-20. PMID:11781089[5]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
See Also
References
- ↑ Meng LM, Kilstrup M, Nygaard P. Autoregulation of PurR repressor synthesis and involvement of purR in the regulation of purB, purC, purL, purMN and guaBA expression in Escherichia coli. Eur J Biochem. 1990 Jan 26;187(2):373-9. PMID:2404765
- ↑ Rolfes RJ, Zalkin H. Purification of the Escherichia coli purine regulon repressor and identification of corepressors. J Bacteriol. 1990 Oct;172(10):5637-42. PMID:2211500
- ↑ Choi KY, Zalkin H. Structural characterization and corepressor binding of the Escherichia coli purine repressor. J Bacteriol. 1992 Oct;174(19):6207-14. PMID:1400170
- ↑ Devroede N, Thia-Toong TL, Gigot D, Maes D, Charlier D. Purine and pyrimidine-specific repression of the Escherichia coli carAB operon are functionally and structurally coupled. J Mol Biol. 2004 Feb 6;336(1):25-42. PMID:14741201
- ↑ Huffman JL, Lu F, Zalkin H, Brennan RG. Role of residue 147 in the gene regulatory function of the Escherichia coli purine repressor. Biochemistry. 2002 Jan 15;41(2):511-20. PMID:11781089
