Solid-state NMR structure determination of whole anchoring threads from the blue mussel Mytilus edulis.

The molecular structure of the blue mussel Mytilus edulis whole anchoring threads was studied by two-dimensional (13)C solid-state NMR on fully labeled fibers. This unique material proves to be well ordered at a molecular level despite its heterogeneous composition as evidenced by the narrow measured linewidths below 1.5 ppm.

Determination of isotopic labeling of proteins by precursor ion scanning liquid chromatography/tandem mass spectrometry of derivatized amino acids applied to nuclear magnetic resonance studies.

Rationale: A method has been developed for the quantitation of isotopic labeling of proteins using liquid chromatography/tandem mass spectrometry (LC/MS/MS) for the application of protein nuclear magnetic resonance (NMR) studies. NMR relies on specific isotopic nuclei, such as (13)C and (15)N, for detection and, therefore, isotopic labeling is an important sample preparation step prior to in-depth structural characterization of proteins. The goal of this study was to develop a robust quantitative assay for assessing isotopic labeling in proteins while retaining information on the extent of labeling for individual amino acids.