Affiliation: | 1. Chemistry & Biochemistry, Calvin College, 1726 Knollcrest Circle SE, Grand Rapids, MI 49546 (USA), Fax: (+1)?616‐526‐6501;2. School of Chemistry and Astbury Center for Structural Molecular Biology, University of Leeds, Leeds, LS2?9JT (UK), Fax: (+44)?113‐343‐6565 |