1x3u
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(New page: 200px<br /><applet load="1x3u" size="450" color="white" frame="true" align="right" spinBox="true" caption="1x3u" /> '''Solution structure of the C-terminal transcr...)
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Revision as of 03:42, 21 November 2007
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Solution structure of the C-terminal transcriptional activator domain of FixJ from Sinorhizobium melilot
Overview
FixJ is a response regulator of the two-component signal transduction, pathway involved in the transcriptional activation of nitrogen fixation, genes of Sinorhizobium meliloti. Upon phosphorylation, FixJ, transcriptionally activates the fixK and nifA promoters. We identified a, FixJ recognition sequence of 16 bp in the high affinity binding site of, the fixK promoter by means of a gel shift assay. In addition, the solution, structure of the truncated C-terminal DNA binding domain of FixJ (FixJC), was solved by NMR spectroscopy. FixJC contains five alpha-helices that, encode a typical helix-turn-helix motif as a potential DNA binding core, with the highest structural similarity toward the C-terminal DNA binding, domain of NarL. The addition of the DNA fragment containing the, recognition sequence of the high affinity FixJ binding site resulted in, intermediate to slow exchange interactions on the NMR time scale in the, spectrum of FixJC, while the exchange was rapid in the case of control, DNA. These spectral data suggest that more than one molecule of FixJC, binds to the recognition sequence, although FixJC alone is present in, monomeric form in solution. This result is consistent with a scenario in, which a transcriptionally active species of FixJ is a homodimer of the, phosphorylated form.
About this Structure
1X3U is a Single protein structure of sequence from Sinorhizobium meliloti. Full crystallographic information is available from OCA.
Reference
Solution structure of the C-terminal transcriptional activator domain of FixJ from Sinorhizobium meliloti and its recognition of the fixK promoter., Kurashima-Ito K, Kasai Y, Hosono K, Tamura K, Oue S, Isogai M, Ito Y, Nakamura H, Shiro Y, Biochemistry. 2005 Nov 15;44(45):14835-44. PMID:16274231
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