1qy7
From Proteopedia
The structure of the PII protein from the cyanobacteria Synechococcus sp. PCC 7942
Structural highlights
FunctionGLNB_SYNE7 P-II indirectly controls the transcription of the GS gene (glnA). P-II prevents NR-II-catalyzed conversion of NR-I to NR-I-phosphate, the transcriptional activator of glnA. When P-II is phosphorylated, these events are reversed. In nitrogen-limiting conditions, when the ratio of Gln to 2-ketoglutarate decreases, P-II is phosphorylated which allows the deadenylation of glutamine synthetase (GS), thus activating the enzyme. 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 PubMedThe PII proteins from the cyanobacteria Synechococcus sp. PCC 7942 and Synechocystis sp. PCC 6803 have been crystallized and high-resolution structures have been obtained using X-ray crystallography. The core of these new structures is similar to that of the PII proteins from Escherichia coli, although the structures of the T- and C-loops differ. The T-loop of the Synechococcus protein is ordered, but appears to be stabilized by crystal contacts. The same loop in the Synechocystis protein is disordered. The C-terminus of the Synechocystis protein is stabilized by hydrogen bonding to the same region of a crystallographically related molecule. The same terminus in the Synechococcus protein is stabilized by coordination with a metal ion. These observations are consistent with the idea that both the T-loop and the C-terminus of PII proteins are flexible in solution and that this flexibility may be important for receptor recognition. Sequence comparisons are used to identify regions of the sequence unique to the cyanobacteria. The structures of the PII proteins from the cyanobacteria Synechococcus sp. PCC 7942 and Synechocystis sp. PCC 6803.,Xu Y, Carr PD, Clancy P, Garcia-Dominguez M, Forchhammer K, Florencio F, Vasudevan SG, Tandeau de Marsac N, Ollis DL Acta Crystallogr D Biol Crystallogr. 2003 Dec;59(Pt 12):2183-90. Epub 2003, Nov 27. PMID:14646076[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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