The Secondary Structure of Human Hageman Factor (Factor XII) and its Alteration by Activating Agents
| Autor: | Oscar D. Ratnoff, Hidehiko Saito, Alan G. Walton, Carl R. McMillin |
|---|---|
| Rok vydání: | 1974 |
| Předmět: |
Circular dichroism
Chemical Phenomena Molecular Conformation Peptide hemic and lymphatic diseases medicine Humans Sodium Hydroxide Benzopyrans Trypsin Amino Acids Tyrosine skin and connective tissue diseases Protein secondary structure chemistry.chemical_classification Clotting factor Factor XII Circular Dichroism Temperature Quartz Articles General Medicine Hydrogen-Ion Concentration Electrophoresis Disc Silicon Dioxide Amino acid Chemistry chemistry Biochemistry Electrophoresis Polyacrylamide Gel Adsorption Hydrochloric Acid sense organs Peptides medicine.drug |
| Zdroj: | Journal of Clinical Investigation. 54:1312-1322 |
| ISSN: | 0021-9738 |
| DOI: | 10.1172/jci107877 |
| Popis: | Hageman factor (factor XII) is activated by exposure to surfaces such as glass or by solutions of certain compounds, notably ellagic acid. Changes in the structure of Hageman factor accompanying activation have been examined in this study by circular dichroism spectroscopy. The spectrum of unactivated Hageman factor in aqueous solutions suggests that its conformation is mainly aperiodic. Various perturbants altered the conformation of Hageman factor in differing ways, demonstrating the sensitivity of Hageman factor to its environment. After activation of Hageman factor with solutions of ellagic acid, a negative trough appeared in the region of the circular dichroism spectrum commonly assigned to tyrosine residues, along with other minor changes in the peptide spectral region. Some of these changes are similar to changes that occurred upon partial neutralization of the basic residues at alkali pH. Activation of Hageman factor by adsorption to quartz surfaces (in an aqueous environment) also produced changes similar to those in the ellagic acid-activated Hageman factor, including the negative ellipticity in the tyrosine region. These observations suggest that the activation process may be related to a change in status of some of the basic amino acid residues, coupled with a specific change in the environment of some tyrosine residues. The importance of these changes during the activation process remains to be determined. The sensitivity of Hageman factor to its environment is consistent with the view that the initiation of clotting by exposure of plasma to appropriate agents is brought about by alterations in the conformation of Hageman factor that occur in the apparent absence of Fletcher factor or other recognized clotting factors. |
| Databáze: | OpenAIRE |
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