Part I: Instrumentation Part II: Equilibrium Methods Part III: Transport Methods Part IV: Specifi... more Part I: Instrumentation Part II: Equilibrium Methods Part III: Transport Methods Part IV: Specific Applications to Biochemical and Polymer Systems
Proteolytic cleavage of the bacterial protein toxin pneumolysin with protease K creates two fragm... more Proteolytic cleavage of the bacterial protein toxin pneumolysin with protease K creates two fragments of 37 and 15 kDa. This paper describes the purification of these two fragments and their subsequent physical and biological characterisation. The larger fragment is directly involved in the cytolytic mechanism of this pore‐forming protein, via membrane binding and self‐association. The smaller fragment lacks ordered structure or discernible activity.
Pneumolysin is a membrane-damaging toxin produced by Streptococcus pneumoniae. In order to unders... more Pneumolysin is a membrane-damaging toxin produced by Streptococcus pneumoniae. In order to understand fully the mode of action of this toxin, it is necessary to have an appreciation of the size, self-association behaviour and solution conformation of pneumolysin. A combination of analytical ultracentrifugation methodologies has shown that pneumolysin lacks self-association behaviour in solution and has provided a weight-average M(r) (M omega) of 52,000 +/- 2000, which was in agreement with that derived from the amino acid sequence. By determining a sedimentation coefficient (S20,w0) of 3.35 +/- 0.10 S, it was possible to suggest a model for the gross solution conformation of pneumolysin monomers. Spectroscopic methods provide additional secondary and tertiary structure information.
The flexible and greatly expanded roughly spherical model for mucus glycoproteins proposed earlie... more The flexible and greatly expanded roughly spherical model for mucus glycoproteins proposed earlier, on the basis of hydrodynamic and n.m.r. data, is supported by new hydrodynamic results on a bronchial glycoprotein from a cystic-fibrosis patient. Furthermore, images from electron microscopy of this molecule and a lower-molecular-weight mucus glycoprotein (which closely resembles a glycopolypeptide) appear to be at least consistent with this model.
The multicatalytic proteinase complex or proteasome is a high-molecular-mass multisubunit protein... more The multicatalytic proteinase complex or proteasome is a high-molecular-mass multisubunit proteinase which is found in the nucleus and cytoplasm of eukaryotic cells. Electron microscopy of negatively stained rat liver proteinase preparations suggests that the particle has a hollow cylindrical shape (approximate width 11 nm and height 17 nm using methylamine tungstate as the negative stain) with a pseudo-helical arrangement of subunits rather than the directly stacked arrangement suggested previously. The side-on view has a 2-fold rotational symmetry, while end-on there appears to be six or seven subunits around the ring. This model is very different from that proposed by others for the proteinase from rat liver but resembles the structure of the simpler archaebacterial proteasome. The possibility of conformational changes associated with the addition of effectors of proteolytic activity has been investigated by sedimentation velocity analysis and dynamic light-scattering measurement...
The conformation and heterogeneity of lambda-carrageenan, a sulphonated galactan from red seaweed... more The conformation and heterogeneity of lambda-carrageenan, a sulphonated galactan from red seaweed, solubilised in aqueous solvent with the assistance of microwave irradiation, has been assessed by a combination of analytical ultracentrifugation, size-exclusion chromatography, light scattering and capillary viscometry. Preparations appeared generally unimodal on the basis of sedimentation coefficient distributions from sedimentation velocity although at the highest concentrations a shoulder appears with a sedimentation coefficient approximately 1.1 times greater than that of the main component. Even under conditions commensurate with charge suppression simple linear regression was insufficient to represent non-ideal concentration dependence and the extraction of the Grálen concentration dependence parameter ks. A more general fitting algorithm was therefore employed. Mark-Houwink-Kuhn-Sakurada analysis of the change in intrinsic viscosity [η] with molecular weight, together with the Wales-van Holde ratio (combination of ks with [η]) point to an extended flexible conformation for lambda-carrageenan in the (weight average) molecular weight range Mw=340,000-870,000g/mol. The origin of the larger sedimentation coefficient component appearing at the higher concentrations is considered.
Ou.sranding unceriarnties in rhe widely employed Simha {J. Phys. Chern. 4.1 (1940) 15) tunction f... more Ou.sranding unceriarnties in rhe widely employed Simha {J. Phys. Chern. 4.1 (1940) 15) tunction for the viscosity increment / of macromolecules as modelled bl" a,xially s_vmmetnc ellipsoids are resolved. A simple development of the anailsis aiso feveals an inreresting relalionship belween, and the translational frictional properiy oi macromolecuies.
Part I: Instrumentation Part II: Equilibrium Methods Part III: Transport Methods Part IV: Specifi... more Part I: Instrumentation Part II: Equilibrium Methods Part III: Transport Methods Part IV: Specific Applications to Biochemical and Polymer Systems
Proteolytic cleavage of the bacterial protein toxin pneumolysin with protease K creates two fragm... more Proteolytic cleavage of the bacterial protein toxin pneumolysin with protease K creates two fragments of 37 and 15 kDa. This paper describes the purification of these two fragments and their subsequent physical and biological characterisation. The larger fragment is directly involved in the cytolytic mechanism of this pore‐forming protein, via membrane binding and self‐association. The smaller fragment lacks ordered structure or discernible activity.
Pneumolysin is a membrane-damaging toxin produced by Streptococcus pneumoniae. In order to unders... more Pneumolysin is a membrane-damaging toxin produced by Streptococcus pneumoniae. In order to understand fully the mode of action of this toxin, it is necessary to have an appreciation of the size, self-association behaviour and solution conformation of pneumolysin. A combination of analytical ultracentrifugation methodologies has shown that pneumolysin lacks self-association behaviour in solution and has provided a weight-average M(r) (M omega) of 52,000 +/- 2000, which was in agreement with that derived from the amino acid sequence. By determining a sedimentation coefficient (S20,w0) of 3.35 +/- 0.10 S, it was possible to suggest a model for the gross solution conformation of pneumolysin monomers. Spectroscopic methods provide additional secondary and tertiary structure information.
The flexible and greatly expanded roughly spherical model for mucus glycoproteins proposed earlie... more The flexible and greatly expanded roughly spherical model for mucus glycoproteins proposed earlier, on the basis of hydrodynamic and n.m.r. data, is supported by new hydrodynamic results on a bronchial glycoprotein from a cystic-fibrosis patient. Furthermore, images from electron microscopy of this molecule and a lower-molecular-weight mucus glycoprotein (which closely resembles a glycopolypeptide) appear to be at least consistent with this model.
The multicatalytic proteinase complex or proteasome is a high-molecular-mass multisubunit protein... more The multicatalytic proteinase complex or proteasome is a high-molecular-mass multisubunit proteinase which is found in the nucleus and cytoplasm of eukaryotic cells. Electron microscopy of negatively stained rat liver proteinase preparations suggests that the particle has a hollow cylindrical shape (approximate width 11 nm and height 17 nm using methylamine tungstate as the negative stain) with a pseudo-helical arrangement of subunits rather than the directly stacked arrangement suggested previously. The side-on view has a 2-fold rotational symmetry, while end-on there appears to be six or seven subunits around the ring. This model is very different from that proposed by others for the proteinase from rat liver but resembles the structure of the simpler archaebacterial proteasome. The possibility of conformational changes associated with the addition of effectors of proteolytic activity has been investigated by sedimentation velocity analysis and dynamic light-scattering measurement...
The conformation and heterogeneity of lambda-carrageenan, a sulphonated galactan from red seaweed... more The conformation and heterogeneity of lambda-carrageenan, a sulphonated galactan from red seaweed, solubilised in aqueous solvent with the assistance of microwave irradiation, has been assessed by a combination of analytical ultracentrifugation, size-exclusion chromatography, light scattering and capillary viscometry. Preparations appeared generally unimodal on the basis of sedimentation coefficient distributions from sedimentation velocity although at the highest concentrations a shoulder appears with a sedimentation coefficient approximately 1.1 times greater than that of the main component. Even under conditions commensurate with charge suppression simple linear regression was insufficient to represent non-ideal concentration dependence and the extraction of the Grálen concentration dependence parameter ks. A more general fitting algorithm was therefore employed. Mark-Houwink-Kuhn-Sakurada analysis of the change in intrinsic viscosity [η] with molecular weight, together with the Wales-van Holde ratio (combination of ks with [η]) point to an extended flexible conformation for lambda-carrageenan in the (weight average) molecular weight range Mw=340,000-870,000g/mol. The origin of the larger sedimentation coefficient component appearing at the higher concentrations is considered.
Ou.sranding unceriarnties in rhe widely employed Simha {J. Phys. Chern. 4.1 (1940) 15) tunction f... more Ou.sranding unceriarnties in rhe widely employed Simha {J. Phys. Chern. 4.1 (1940) 15) tunction for the viscosity increment / of macromolecules as modelled bl" a,xially s_vmmetnc ellipsoids are resolved. A simple development of the anailsis aiso feveals an inreresting relalionship belween, and the translational frictional properiy oi macromolecuies.
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Papers by Arthur Rowe