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Title
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Nuclear magnetic resonance assignments and global fold of a CheY-binding domain in CheA, the chemotaxis-specific kinase of Escherichia coli.
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Authors
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M.M.McEvoy,
H.Zhou,
A.F.Roth,
D.F.Lowry,
T.B.Morrison,
L.E.Kay,
F.W.Dahlquist.
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Ref.
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Biochemistry, 1995,
34,
13871-13880.
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PubMed id
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Abstract
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CheA is the histidine autokinase in the Escherichia coli chemotaxis signal
transduction pathway responsible for coupling of signals received by
transmembrane receptors to the response regulators CheY and CheB. Here NMR
spectroscopy is used to study a 14 kDa fragment of CheA, residues 124-257, that
binds the response regulator CheY. Backbone atom resonance assignments were
obtained by analysis of 3D HNCACB, 3D CBCA(CO)NH, and HNCO spectra, whereas
side-chain assignments were obtained primarily by analysis of 3D H(CCO)NH, 3D
C(CO)NH, 3D HCCH-TOCSY, and 3D 1H, 15N TOCSY-HSMQC spectra. NOE cross peak
patterns and intensities as well as torsion angle restraints were used to
determine the secondary structure, and a low-resolution structure was calculated
by hybrid distance-geometry simulated annealing methods. The CheA124-257
fragment consists of four antiparallel beta strands and two helices, arranged in
an "open-faced beta-sandwich" motif, as well as two unstructured ends that
correspond to domain linkers in the full-length protein. The 15N-1H correlation
spectrum of 15N-labeled CheA124-257 bound to unlabeled CheY shows specific
localized changes that may correspond to a CheY-binding face on CheA.
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