Molecular Level Understanding of Biological Systems with High Motional Heterogeneity in Its Absolute Native State

Abstract

Biological tissues possessing motional heterogeneity are difficult to comprehend at atomic level in their native state. Some of these tissues play crucial roles in support and movement of the body. Articular cartilage is one such tissue exemplified with highly mobile glycosaminoglycans (GAGS, correlation time ∼10–9s) and relatively rigid collagen protein (correlation time ∼10–6 s). Simultaneous study of both the components at atomic level is challenging and requires different sets of solid state nuclear magnetic resonance (ssNMR) experiments for mobile and rigid parts. Additionally, it is hard to get any quantitative information as one 13C one pulse experiment is time-consuming. We present here a 13C ssNMR experiment with complete molecular characterization of cartilage organic components in its native state. We achieved this by employing heteronuclear Overhauser enhancement with equilibration of magnetization by low power irradiation. Complete 13C resonances from GAGS and collagen were identified simulta...