title: Order parameters of the orientation distribution of collagen fibers in Achilles tendon by 1H NMR of multipolar spin states.
abstract: The angular distribution function of collagen fibrils in a sheep Achilles tendon was investigated by (1)H NMR of multipolar spin states represented by dipolar-encoded longitudinal magnetization and double-quantum filtered signals. For the first time the angular distribution function based on the Legendre moment expansion is used. Order parameters were obtained from the anisotropy of (1)H residual dipolar couplings of bond water, which were determined model-free from the excitation efficiency of the multipolar spin states and from double-quantum filtered line splitting. The orientation distribution function of collagen fibrils in Achilles tendon measured from the anisotropy of the residual dipolar couplings is characterized by the average values of beta0 = 1.8+/-0.2 degrees and order parameters [P2] = 0.93+/-0.04, [P4] = 0.78+/-0.04 and [P6] = 0.58+/-0.04. The order of many biological tissues in the presence of ageing, injuries or regeneration can be quantified by the order parameters of the angular distribution function.
authors.affiliation: Institut für Technische Chemie und Makromolekulare Chemie, Rheinisch-Westfälische Technische Hochschule, Worringerweg 1, D-52056 Aachen, Germany.
authors.forename: R
authors.initials: R
authors.lastname: Fechete
authors.forename: D E
authors.initials: DE
authors.lastname: Demco
authors.forename: B
authors.initials: B
authors.lastname: Blümich
mesh_terms: D000125:Achilles Tendon / Q000737:chemistry* / Q000648:ultrastructure*; D000818:Animals; D016880:Anisotropy; D003094:Collagen / Q000032:analysis / Q000737:chemistry* / Q000648:ultrastructure*; D066298:In Vitro Techniques; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D011487:Protein Conformation; D011522:Protons; D012756:Sheep; D013113:Spin Labels; D014867:Water / Q000737:chemistry*
chemical_list: D011522:Protons; D013113:Spin Labels; D014867:Water; D003094:Collagen