Wideline Separation (WISE) NMR of Native Elastin

Abstract

Native elastin is an insoluble, amorphous (noncrystalline) protein with significant hydrophobic character. As its name suggests, the elasticity of blood vessels and other tissue types in vertebrates originates from this protein. We have previously shown that there is significant structural heterogeneity in this protein and its mimetics, and our earlier data indicated that its dynamic profile includes motions under multiple time scales. To examine this picture further, we use WIdeline SEparation (WISE) NMR experiments to characterize the natural-abundance 13C populations of unenriched elastin in fully hydrated and lyophilized states. The hydrated elastin has only one peak in the indirect dimension, reflective of significant motional narrowing. In contrast, the lyophilized elastin has a broad feature, indicating limited or no motion. In addition, however, our results indicate that a faster motion is also present, even in the absence of the water. The details of the line fitting and the possible implications for elastin are discussed.

Probing the Motional Behavior of Eumelanin and Pheomelanin with Solid‐State NMR Spectroscopy: New Insights into the Pigment Properties

“…Analysis of LG‐WISE experiments : To extract information about the mobility of the black and red melanin in the two samples, a quantitative analysis of the 1 H line shapes extracted from the 2D 1 H– 13 C LG WISE spectra was performed 35. In all the cases, the 1 H line shapes were fitted by using a combination of equations ((2) and(3)) previously described by Emsley and co‐workers36 and recently used by Kumashiro and co‐workers to study the mobility of elastin:37, …”

Solid-State NMR Spectroscopy and Isotopic Labeling Target Abundant Dipeptide Sequences in Elastin’s Hydrophobic Domains

“…Solid-state nuclear magnetic resonance (NMR) spectroscopy is a powerful tool for the study of the structure and dynamics of elastin. − The inherent mobility in hydrated elastin precludes the application of dipolar-based methods like cross-polarization. , Alternatively, J -coupling-based experiments are compatible with the rapid fluctuations in this protein. Recently, we reported the characterization of hydrated 15 N-enriched recombinant elastin using the refocused insensitive nuclei enhanced by polarization transfer (rINEPT) technique. , …”

Resolving Nitrogen-15 and Proton Chemical Shifts for Mobile Segments of Elastin with Two-dimensional NMR Spectroscopy

“…Recent two-dimensional NMR experiments provided additional insights into the multiple conformations that are present in native elastin (8,9), but these studies were conducted using unenriched elastin, as they focused on the natural abundance 13 C populations of the protein. These experiments, however, were more informative for the lyophilized elastin than for the hydrated form.…”