Multidimensional Solid-State Nuclear Magnetic Resonance of a Functional Multiprotein Chemoreceptor Array.
The bacterial chemoreceptor complex governs signal detection and the upstream elements of chemotactic behavior, but the detailed molecular mechanism is still unclear. We have assembled nativelike functional arrays of an aspartate receptor cytoplasmic fragment (CF) with its two cytoplasmic protein partners (CheA and CheW) for solid-state nuclear magnetic resonance (NMR) studies of structural changes involved in signaling. In this initial study of the uniformly (13)C- and (15)N-enriched CF in these >13.8 MDa size arrays, residue-type assignments are made for amino acids that together make up 90% of the protein. We demonstrate that homo- and heteronuclear two-dimensional spectra are consistent with structure-based chemical shift predictions: a number of major assignable correlations are consistent with the predominantly α-helical secondary structure, and minor correlations are consistent with the disordered C-terminal tail. Sub-parts per million line widths and spectral changes upon freezing of samples suggest these arrays are structurally homogeneous and sufficiently immobilized for efficient solid-state NMR.
Department of Chemistry, University of Massachusetts , 710 North Pleasant Street, Amherst, Massachusetts 01003, United States.
Michael J
MJ
Harris
Bruker BioSpin Corporation , 15 Fortune Drive, Billerica, Massachusetts 01821, United States.
Jochem O
JO
Struppe
Department of Chemistry, Columbia University , 3000 Broadway, New York, New York 10027, United States.
Benjamin J
BJ
Wylie
Department of Chemistry, Columbia University , 3000 Broadway, New York, New York 10027, United States.
Ann E
AE
McDermott
Department of Chemistry, University of Massachusetts , 710 North Pleasant Street, Amherst, Massachusetts 01003, United States.
Lynmarie K
LK
Thompson
D004926:Escherichia coli / Q000378:metabolism*; D029968:Escherichia coli Proteins / Q000737:chemistry* / Q000378:metabolism; D008958:Models, Molecular; D019906:Nuclear Magnetic Resonance, Biomolecular; D017433:Protein Structure, Secondary; D011956:Receptors, Cell Surface / Q000737:chemistry*
D029968:Escherichia coli Proteins; D011956:Receptors, Cell Surface