A 13C labeling strategy reveals a range of aromatic side chain motion in calmodulin. Academic Article uri icon


  • NMR relaxation experiments often require site-specific isotopic enrichment schemes in order to allow for quantitative interpretation. Here we describe a new labeling scheme for site-specific (13)C-(1)H enrichment of a single ortho position of aromatic amino acid side chains in an otherwise perdeuterated background by employing a combination of [4-(13)C]erythrose and deuterated pyruvate during growth on deuterium oxide. This labeling scheme largely eliminates undesired contributions to (13)C relaxation and greatly simplifies the fitting of relaxation data using the Lipari-Szabo model-free formalism. This approach is illustrated with calcium-saturated vertebrate calmodulin and oxidized flavodoxin from Cyanobacterium anabaena . Analysis of (13)C relaxation in the aromatic groups of calcium-saturated calmodulin indicates a wide range of motion in the subnanosecond time regime.

published proceedings

  • J Am Chem Soc

altmetric score

  • 3.5

author list (cited authors)

  • Kasinath, V., Valentine, K. G., & Wand, A. J.

citation count

  • 42

complete list of authors

  • Kasinath, Vignesh||Valentine, Kathleen G||Wand, A Joshua

publication date

  • July 2013