An efficient 3D NMR technique for correlating the proton and15N backbone amide resonances with the α-carbon of the preceding residue in uniformly15N/13C enriched proteins
A 3D NMR technique is described which correlates the amide proton and nitrogen resonances of an amino acid residue with the Cα chemical shift of its preceding residue. The technique uses a relay mechanism, transferring magnetization from15N to13Cα via the intervening carbonyl nucleus. This method for obtaining sequential connectivity is less sensitive to large line widths than the alternative HNCA experiment. The technique is demonstrated for the protein calmodulin, complexed with a 26 amino acid fragment of skeletal muscle myosin light chain kinase.
Keywords3D NMRTriple resonance assignmentHeteronuclearCalmodulin
α-proton to α-carbon to carbonyl correlation
α-proton (via α-carbon) to nitrogen to amide proton correlation
heteronuclear multiple quantum correlation
amide proton to nitrogen to C α-carbon correlation
a 26-residue fragment of the CaM-binding domain of skeletal muscle myosin light chain kinase comprising residues 577–602.