1. New Mexico Consortium; Los Alamos, NM USA
2. Present address: National Institute for Biological Standards and Control (NIBSC), Potters Bar, Hertfordshire, UK
3. Los Alamos National Laboratory; Los Alamos, NM USA
4. Structural Genomics Consortium, University of Toronto, Toronto, ON Canada
5. University of Oslo; Oslo, Norway
6. Università del Piemonte Orientale; Novara, Italy