2rd5 | pdb_00002rd5
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| 2rd5, resolution 2.51Å | |||||||||||||
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| Ligands: | ADP, ARG, ATP, MG, NLG | ||||||||||||
| Gene: | T8H10.160 (Arabidopsis thaliana), AT4g01900, T7B11.16 (Arabidopsis thaliana) | ||||||||||||
| Activity: | Acetylglutamate kinase, with EC number 2.7.2.8 | ||||||||||||
| Related: | 2O66, 2O67
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| Resources: | FirstGlance, OCA, PDBsum, RCSB | ||||||||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||||||||
Structural basis for the regulation of N-acetylglutamate kinase by PII in Arabidopsis thaliana
Overview
PII is a highly conserved regulatory protein found in organisms across the three domains of life. In cyanobacteria and plants, PII relieves the feedback inhibition of the rate-limiting step in arginine biosynthesis catalyzed by N-acetylglutamate kinase (NAGK). To understand the molecular structural basis of enzyme regulation by PII, we have determined a 2.5-A resolution crystal structure of a complex formed between two homotrimers of PII and a single hexamer of NAGK from Arabidopsis thaliana bound to the metabolites N-acetylglutamate, ADP, ATP, and arginine. In PII, the T-loop and Trp(22) at the start of the alpha1-helix, which are both adjacent to the ATP-binding site of PII, contact two beta-strands as well as the ends of two central helices (alphaE and alphaG) in NAGK, the opposing ends of which form major portions of the ATP and N-acetylglutamate substrate-binding sites. The binding of Mg(2+).ATP to PII stabilizes a conformation of the T-loop that favors interactions with both open and closed conformations of NAGK. Interactions between PII and NAGK appear to limit the degree of opening and closing of the active-site cleft in opposition to a domain-separating inhibitory effect exerted by arginine, thus explaining the stimulatory effect of PII on the kinetics of arginine-inhibited NAGK.
About this Structure
2RD5 is a Protein complex structure of sequences from Arabidopsis thaliana. Full crystallographic information is available from OCA.
Reference
Structural basis for the regulation of N-acetylglutamate kinase by PII in Arabidopsis thaliana., Mizuno Y, Moorhead GB, Ng KK, J Biol Chem. 2007 Dec 7;282(49):35733-40. Epub 2007 Oct 3. PMID:17913711
Page seeded by OCA on Mon Mar 31 04:59:04 2008
