1. Department of Microbiology, University of Virginia, Charlottesville 22908, USA.
2. Hendrickson, Department of Chemistry, University of Virginia, Charlottesville, VA 22901, USA.
3. Department of lmmunohaematology and Blood Bank, Leiden University Hospital, Netherlands.
4. Promega Corporation, Madison, WI 53711, USA.
5. Departments of Obstetrics and Gynecology and Human and Molecular Genetics, Baylor College of Medicine, Houston, TX 77030, USA.
6. Departments of Chemistry and Pathology, University of Virginia, Charlottesville, VA 22903, USA.