Cover illustration
Cover photograph: X-ray radiation from a synchrotron source can rapidly damage a protein crystal and impede data interpretation.The nine images illustrate a time course of electron density mapsfrom the same protein crystal. Protein degradation is indicatedby the disappearance of the disulfide bond (empty blue cage) linkingthe carbon chains (white balls). See article by Weik et al. onpages 623-628 in thisissue.