Magnesium binding to the bacterial chemotaxis protein CheY results in large conformational changes involving its functional surface.
The three-dimensional crystal structure of the bacterial chemotaxis protein CheY with the essential Mg2+ cation bound to the active site reveals large conformational changes caused by the metal binding. Displacements of up to 10 A are observed in several residues at the N terminus of alpha-helix 4 and in the preceding loop. One turn of this helix unwinds, and an Asn residue that was located inside the helix becomes the new N-cap. This supports the important role that N or C-cap residues play in alpha-helix stability. In addition the preceding beta-strand becomes elongated and a new beta-turn appears. The final effect is a significant modification of the surface relief of the protein in a region previously indicated, by genetic analysis, to be essential for CheY function. It is suggested that binding of a divalent cation to CheY could play a significant part in CheY activation and consequently in signal transduction in prokaryotes.
Bellsolell
L
L
Departament de Biologia Molecular i Cel.lular, Centre d'Investigació iDesenvolupament, CSIC, Barcelona, Spain.
Prieto
J
J
Serrano
L
L
Coll
M
M
D001426:Bacterial Proteins; D001665:Binding Sites; D002633:Chemotaxis; D003196:Computer Graphics; D006860:Hydrogen Bonding; D008239:Lysine / Q000737:chemistry; D008274:Magnesium / Q000378:metabolism*; D008565:Membrane Proteins / Q000737:chemistry* / Q000378:metabolism; D000072236:Methyl-Accepting Chemotaxis Proteins; D008958:Models, Molecular; D011487:Protein Conformation; D011494:Protein Kinases / Q000737:chemistry* / Q000378:metabolism; D017433:Protein Structure, Secondary
D001426:Bacterial Proteins; D008565:Membrane Proteins; D000072236:Methyl-Accepting Chemotaxis Proteins; D011494:Protein Kinases; D008274:Magnesium; D008239:Lysine