Electric birefringence studies of cartilage proteoglycan aggregation

Foweraker, A.R.; Isles, M.; Jennings, B. R.; Hardingham, Timothy E.; Muir, Helen

doi:10.1002/bip.1977.360160617

Cited by 11 publications

(6 citation statements)

References 8 publications

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“…Dynamic light scattering (DLS) on dilute aggrecan solutions allowed the measurement of the hydrodynamic radii of the internal modes of a monomer (44 ± 7 nm) and the size of a monomer (202 ± 10 nm). The monomer size is in reasonable agreement with AFM 26 and electric birefringence experiments . The fast mode corresponds to internal longitudinal breathing modes of the aggrecan monomer side-chains.…”

Section: Discussionsupporting

confidence: 79%

“…In the aggregated state, aggrecan monomers are physically bound onto a hyaluronic acid chain. Aggrecan monomers consist of a ∼400 nm protein backbone with approximately one hundred highly negatively charged side chains, each ∼40 nm in length which are predominantly chondroitin sulfate glycosaminoglycan (CS-GAG). , Additional shorter side-chains of keratan sulfate also occur. Aggrecan is found in cartilage, mainly as aggregates involving hyaluronic acid (major axis of the ellipsoid is ∼2000 nm) .…”

Section: Methodsmentioning

confidence: 99%

“…Aggrecan monomers consist of a ∼400 nm protein backbone with approximately one hundred highly negatively charged side chains, each ∼40 nm in length which are predominantly chondroitin sulfate glycosaminoglycan (CS-GAG). , Additional shorter side-chains of keratan sulfate also occur. Aggrecan is found in cartilage, mainly as aggregates involving hyaluronic acid (major axis of the ellipsoid is ∼2000 nm) . The aggregate is thought to consist of an extended hyaluronic acid chain to which the aggrecan monomers are regularly attached.…”

Section: Methodsmentioning

confidence: 99%

“…Aggrecan is found in cartilage, mainly as aggregates involving hyaluronic acid (major axis of the ellipsoid is ∼2000 nm). 32 The aggregate is thought to consist of an extended hyaluronic acid chain to which the aggrecan monomers are regularly attached. Each aggrecan monomer has a globular protein head which binds to the hyaluronic acid backbone.…”

Section: Methodsmentioning

confidence: 99%

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Solution Structure and Dynamics of Cartilage Aggrecan

et al. 2006

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We studied the structure and dynamics of porcine laryngeal aggrecan in solution using a range of noninvasive techniques: dynamic light scattering (DLS), small-angle neutron scattering (SANS), video particle tracking (VPT) microrheology, and diffusing wave spectroscopy (DWS). The data are analyzed within the framework of a combined static and dynamic scaling model, and evidence is found for reptation of the comb backbones with unentangled side-chain dynamics. Small-angle neutron scattering indicated standard polyelectrolyte scaling of the mesh size (xi) with concentration (c) in semidilute solutions for the whole aggrecan aggregate, xi = Ac(-0.47+/-0.04), with the prefactor (A) implying there is on average 60 nm between the aggrecan subunits along the backbone. VPT demonstrated large exponents for the power law dependence of the intrinsic viscosity (eta) on the polymer concentration in the semidilute concentration regime, eta approximately c(alpha); with alpha equal to 2.04 +/- 0.06 and 1.95 +/- 0.08 for the assembled and disassembled aggrecan aggregates, respectively. DWS at high frequencies (10(4)-10(5) Hz) gave evidence for internal Rouse modes of the aggrecan monomers, independent of the degree of self-assembly of the molecules.

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Section: Discussionsupporting

confidence: 79%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

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Solution Structure and Dynamics of Cartilage Aggrecan

et al. 2006

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“…= 0.1 to 0.5% and C, = 0.5 MNaC1 by light scattering. The sign inversion of electric birefringence by aggregation was observed by Foweraker et al for proteoglycan [27].…”

Section: Relaxation Cmentioning

confidence: 74%

Relaxational behavior of birefringence of aqueous carboxymethylcellulose under an alternating electric field at frequencies ranging from 0.1 Hz to 100 kHz

Yamamoto

Mori

Ookubo

et al. 1982

Colloid & Polymer Sci

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The d. c. component of birefringence of aqueous carboxymethylcellulose (CMC) under an a. c. electric field was measured at frequencies ranging from 0.1 Hz to 100 kHz. Three samples of different molecular weights were studied with varying degree of neutralization, polymer concentration and added salt concentration. The dispersion curve of birefringence consists of three relaxation bands, A, B and C in order of decreasing frequency. Relaxation B with a negative relaxation strength is ascribed to end-over-end rotation of almost rodlike CMC molecules. Relaxation A with a positive strength is attributed to the relaxation of electrical polarizability along the minor axis of molecule. Relaxation C possesses also a positive strength and is induced by clusters of CMC molecules.

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Hydrodynamic properties of proteoglycan subunit from bovine nasal cartilage. Self‐association behaviour and interaction with hyaluronate studied by laser light scattering

et al. 1979

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SynopsisMeasurements of translational diffusion coefficients by quasielastic laser light scattering, sedimentation coefficients, and intrinsic viscosities a t zero shear of proteoglycan subunit fraction A1-D1-D1 isolated from bovine nasal septa are reported. Molecular weights and hydrodynamic dimensions are compared with those expected on the basis of structural models previously proposed. Comparison of the concentration dependence of the diffusion coefficient in the presence of NaCl and GdnHCl leads to the conclusion that significant self-association behavior of subunit occurs in the absence of GdnHCl. In the absence of added salt, anomalous nonlinear concentration dependence of Dt estimated from wide-angle light-scattering experiments is observed. In addition, Dt apparently becomes angle dependent. These results are interpreted in terms of the perturbation of normal translational diffusion of the monomer by strong repulsive intermolecular interactions due to the combined effects of long-range electrostatic forces and macromolecular congestion a t higher concentrations. By carrying out experiments a t small scattering angles, it is possible to determine Dp for proteoglycan subunit in the absence of supporting electrolyte. Titration of a dilute solution of subunit with hyaluronic acid results in a sigmoidal behavior of the Stokes radius, indicating the formation of complexes of higher molecular weight results from the noncovalent association of proteoglycan subunits with hyaluronate. Observation of Dt appears to provide a useful method for studying the proteoglycan subunit-hyaluronate interactions.

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Electric birefringence studies of cartilage proteoglycan aggregation

Cited by 11 publications

References 8 publications

Solution Structure and Dynamics of Cartilage Aggrecan

Solution Structure and Dynamics of Cartilage Aggrecan

Relaxational behavior of birefringence of aqueous carboxymethylcellulose under an alternating electric field at frequencies ranging from 0.1 Hz to 100 kHz

Hydrodynamic properties of proteoglycan subunit from bovine nasal cartilage. Self‐association behaviour and interaction with hyaluronate studied by laser light scattering

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