Publications [#113172] of Harold P. Erickson

Papers Published

1. K Ohmori, LJ Fretto, RL Harrison, ME Switzer, HP Erickson, PA McKee, Electron microscopy of human factor VIII/Von Willebrand glycoprotein: effect of reducing reagents on structure and function., The Journal of cell biology, UNITED STATES, vol. 95 no. 2 Pt 1 (November, 1982), pp. 632-40, ISSN 0021-9525
   (last updated on 2009/02/12)

   Abstract:
   The structure of native and progressively reduced human factor VIII/von Willebrand factor (FVIII/vWF) was examined by electron microscopy and SDS gel electrophoresis and then correlated with its biological activities. Highly resolved electron micrographs of well-spaced, rotary-shadowed FVIII/vWF molecules showed their structure to consist of a very flexible filament that contains irregularly spaced small nodules. Filaments ranged from 50 to 1,150 nm with a mean length of 478 nm and lacked fixed, large globular domains as seen in fibrinogen and IgM. A population of multimeric FVIII/vWF species ranging in molecular weight from 1 to 5 million daltons and differing in size alternately by one and two subunits was observed on SDS-2% polyacrylamide-0.5% agarose gel electrophoresis. With progressive reduction of disulfide bonds by dithiothreitol (DTT), the electron microscopic size of FVIII/vWF decreased in parallel with increased electrophoretic mobility on SDS-agarose gels; between 0.1 and 0.5 mM DTT its structure changed from predominantly fibrillar species to large nodular forms. A 50% loss of vWF specific activity and FVIII procoagulant activity occurred at 0.4 mM DTT and 1 mM DTT, respectively, corresponding to the reduction of 4 and 12 disulfide bonds of the 62 disulfides per 200,000-dalton subunit. We conclude that reduction of a few critical disulfide bonds results in a major structural change by electron microscopy and a concomitant loss of approximately 50% of the vWF function.

   Keywords:
   Alkylation • Blood Coagulation Factors* • Blood Platelets • Dithiothreitol • Factor VIII* • Humans • Macromolecular Substances • Mercaptoethanol • Microscopy, Electron • Molecular Weight • Platelet Aggregation • Protein Conformation • Ristocetin • Structure-Activity Relationship • metabolism • pharmacology • pharmacology* • physiology • von Willebrand Factor*