| has gloss | eng: HNCOCA is a 3D NMR experiment commonly used in the field of protein NMR. The name derives from the experiments magnetization transfer pathway: The magnetization of the amide proton of an amino acid residue is transferred to the amide nitrogen, and then to the alpha carbon of the previous residue in the proteins amino acid sequence. In contrast, the complementary HNCA experiment transfers magnetization to the alpha carbons of both the starting residue and the previous residue in the sequence. The HNCOCA experiment is used, often in tandem with HNCA, to assign alpha carbon resonance signals to specific residues in the protein. This experiment requires a purified sample of protein prepared with 13C and 15N isotopic labelling, at a concentration greater than 0.1 mM, and is thus generally only applied to recombinant proteins. |
