There is a number of 'defined' anions known from structures of halorhodopsin and the cores of coiled-coil proteins often show them as well.
---------------------------------------------- Kornelius Zeth Max Planck Institute for Developmental Biology Dept. Protein Evolution Spemannstr. 35 72076 Tuebingen, Germany [EMAIL PROTECTED] Tel -49 7071 601 323 Fax -49 7071 601 349
