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Full-Text Articles in Physical Sciences and Mathematics

Chess, Chance And Conspiracy, Mark Segal Dec 2006

Chess, Chance And Conspiracy, Mark Segal

Mark R Segal

Chess and chance are seemingly strange bedfellows. Luck and/or randomness have no apparent role in move selection when the game is played at the highest levels. However, when competition is at the ultimate level, that of the World Chess Championship (WCC), chess and conspiracy are not strange bedfellows, there being a long and colorful history of accusations levied between participants. One such accusation, frequently repeated, was that all the games in the 1985 WCC (Karpov vs Kasparov) were fixed and prearranged move by move. That this claim was advanced by a former World Champion, Bobby Fischer, argues that it ought …


The Extracellular Chaperone Clusterin Influences Amyloid Formation And Toxicity By Interacting With Pre-Fibrillar Structures, Justin Yerbury, Stephen Poon, Sarah Meehan, Brianna Thompson, Janet Kumita, Christopher Dobson, Mark Wilson Dec 2006

The Extracellular Chaperone Clusterin Influences Amyloid Formation And Toxicity By Interacting With Pre-Fibrillar Structures, Justin Yerbury, Stephen Poon, Sarah Meehan, Brianna Thompson, Janet Kumita, Christopher Dobson, Mark Wilson

Mark R Wilson

Clusterin is an extracellular chaperone present in all disease-associated extracellular amyloid deposits, however, its roles in amyloid formation and protein deposition in vivo are poorly understood. The current study initially aimed to characterise the effects of clusterin on amyloid formation in vitro by a panel of eight protein substrates. Two of the substrates (Alzheimer's beta peptide and a PI3-SH3 domain) were then used in further experiments to examine the effects of clusterin on amyloid cytotoxicity and to probe the mechanism of clusterin action. We show that clusterin exerts potent effects on amyloid formation, the nature and extent of which vary …


The Extracellular Chaperone Clusterin Potently Inhibits Human Lysozyme Amyloid Formation By Interacting With Prefibrillar Species, Mark Wilson, Justin Yerbury, Stephen Poon, Christopher Dobson, C V Robinson, Elise Stewart, Janet Kumita, Mireille Dumoulin, Gemma Caddy, Christine Hagan Dec 2006

The Extracellular Chaperone Clusterin Potently Inhibits Human Lysozyme Amyloid Formation By Interacting With Prefibrillar Species, Mark Wilson, Justin Yerbury, Stephen Poon, Christopher Dobson, C V Robinson, Elise Stewart, Janet Kumita, Mireille Dumoulin, Gemma Caddy, Christine Hagan

Mark R Wilson

We have studied the effects of the extracellular molecular chaperone, clusterin, on the in vitro aggregation of mutational variants of human lysozyme, including one associated with familial amyloid disease. The aggregation of the amyloidogenic variant I56T is inhibited significantly at clusterin-to-lysozyme ratios as low as 1:80 (i.e. one clusterin molecule per 80 lysozyme molecules). Experiments indicate that under the conditions where inhibition of aggregation occurs, clusterin does not bind detectably to the native or fibrillar states, or to the monomeric transient intermediate known to be a key species in the aggregation reaction. Rather, it seems to interact with oligomeric species …


Effects Of Glycosylation On The Structure And Function Of The Extracellular Chaperone Clusterin, Elise Stewart, Andrew Aquilina, Simon B Easterbrook-Smith, D Murphy-Durland, C Jacobsen, S Moestrup, Mark Wilson Dec 2006

Effects Of Glycosylation On The Structure And Function Of The Extracellular Chaperone Clusterin, Elise Stewart, Andrew Aquilina, Simon B Easterbrook-Smith, D Murphy-Durland, C Jacobsen, S Moestrup, Mark Wilson

Mark R Wilson

Clusterin is the first well characterized, constitutively secreted extracellular chaperone that binds to exposed regions of hydrophobicity on non-native proteins. It may help control the folding state of extracellular proteins by targeting them for receptor-mediated endocytosis and intracellular lysosomal degradation. A notable feature of secreted clusterin is its heavy glycosylation. Although carbohydrate comprises approximately 20−25% of the total mass of the mature molecule, its function is unknown. Results from the current study demonstrate that deglycosylation of human serum clusterin had little effect on its overall secondary structure content but produced a small increase in solvent-exposed hydrophobicity and enhanced the propensity …