1r62
From Proteopedia
Crystal structure of the C-terminal Domain of the Two-Component System Transmitter Protein NRII (NtrB)
Structural highlights
Function[NTRB_ECOLI] NtrB acts as a signal transducer which responds to the nitrogen level of cell and modulates the activity of NtrC. In nitrogen limitation NtrB activates NtrC by phosphorylating it, while in nitrogen excess NtrC is dephosphorylated and consequently inactivated by NtrB. 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 kinase/phosphatase nitrogen regulator II (NRII, NtrB) is a member of the transmitter protein family of conserved two-component signal transduction systems. The kinase activity of NRII brings about the phosphorylation of the transcription factor nitrogen regulator I (NRI, NtrC), causing the activation of Ntr gene transcription. The phosphatase activity of NRII results in the inactivation of NRI-P. The activities of NRII are regulated by the signal transduction protein encoded by glnB, PII protein, which upon binding to NRII inhibits the kinase and activates the phosphatase activity. The C-terminal ATP-binding domain of NRII is required for both the kinase and phosphatase activities and contains the PII binding site. Here, we present the crystal structure of the C-terminal domain of a mutant form of NRII, NRII-Y302N, at 1.6 A resolution and compare this structure to the analogous domains of other two-component system transmitter proteins. While the C-terminal domain of NRII shares the general tertiary structure seen in CheA, PhoQ, and EnvZ transmitter proteins, it contains a distinct beta-hairpin projection that is absent in these related proteins. This projection is near the site of a well-characterized mutation that reduces the binding of PII and near other less-characterized mutations that affect the phosphatase activity of NRII. Sequence alignment suggests that the beta-hairpin projection is present in NRII proteins from various organisms, and absent in other transmitter proteins from Escherichia coliK-12. This unique structural element in the NRII C-terminal domain may play a role in binding PII or in intramolecular signal transduction. Crystal structure of the C-terminal domain of the two-component system transmitter protein nitrogen regulator II (NRII; NtrB), regulator of nitrogen assimilation in Escherichia coli.,Song Y, Peisach D, Pioszak AA, Xu Z, Ninfa AJ Biochemistry. 2004 Jun 1;43(21):6670-8. PMID:15157101[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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Categories: Ecoli | Ninfa, A J | Peisach, D | Pioszak, A A | Song, Y | Xu, Z | Histidine kinase | Nrii | Pii | Transferase | Two component system
