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2rd5
From Proteopedia
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'''Structural basis for the regulation of N-acetylglutamate kinase by PII in Arabidopsis thaliana''' | '''Structural basis for the regulation of N-acetylglutamate kinase by PII in Arabidopsis thaliana''' | ||
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[[Category: Moorhead, G B.G.]] | [[Category: Moorhead, G B.G.]] | ||
[[Category: Ng, K K.S.]] | [[Category: Ng, K K.S.]] | ||
| - | [[Category: | + | [[Category: Kinase]] |
| - | [[Category: | + | [[Category: Nitrogen metabolism]] |
| - | [[Category: | + | [[Category: Protein binding]] |
| - | [[Category: | + | [[Category: Protein-protein complex]] |
| - | [[Category: | + | [[Category: Regulation of arginine biosynthesis]] |
| - | [[Category: | + | [[Category: Transcription]] |
| - | [[Category: | + | [[Category: Transcription regulation]] |
| - | [[Category: | + | [[Category: Transferase]] |
| - | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sun May 4 16:40:28 2008'' | |
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on | + | |
Revision as of 13:40, 4 May 2008
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 Sun May 4 16:40:28 2008
