1dc7: Difference between revisions

[[Image:1dc7.jpg|left|200px]]

'''STRUCTURE OF A TRANSIENTLY PHOSPHORYLATED "SWITCH" IN BACTERIAL SIGNAL TRANSDUCTION'''

Receiver domains are the dominant molecular switches in bacterial signalling. Although several structures of non-phosphorylated receiver domains have been reported, a detailed structural understanding of the activation arising from phosphorylation has been impeded by the very short half-lives of the aspartylphosphate linkages. Here we present the first structure of a receiver domain in its active state, the phosphorylated receiver domain of the bacterial enhancer-binding protein NtrC (nitrogen regulatory protein C). Nuclear magnetic resonance spectra were taken during steady-state autophosphorylation/dephosphorylation, and three-dimensional spectra from multiple samples were combined. Phosphorylation induces a large conformational change involving a displacement of beta-strands 4 and 5 and alpha-helices 3 and 4 away from the active site, a register shift and an axial rotation in helix 4. This creates an exposed hydrophobic surface that is likely to transmit the signal to the transcriptional activation domain.

1DC7 is a [[Single protein]] structure of sequence from [http://en.wikipedia.org/wiki/Salmonella_typhimurium Salmonella typhimurium]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1DC7 OCA].  

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