title: A new aspect of specific radiation damage: hydrogen abstraction from organic molecules.
abstract: Radiation damage is one of the major impediments in obtaining high-resolution structural information utilizing ionizing radiation. From electron microscopy it is known that electron irradiation of biological samples results in the formation of molecular hydrogen. In the present work radiation-induced structural changes of the polypeptide cyclosporine A were observed at a temperature of 100 K. Bond length changes are thought to be due to radiation-induced hydrogen abstraction which chemically modifies the molecules in an irreversible way. The resulting formation of molecular hydrogen might explain the observed increase of the crystal mosaicity, which has also been reported in many previous radiation damage studies.
authors.affiliation: HASYLAB-DESY, Notkestrasse 85, D-22607 Hamburg, Germany. alke.meents@desy.de
authors.forename: Alke
authors.initials: A
authors.lastname: Meents
authors.forename: Birger
authors.initials: B
authors.lastname: Dittrich
authors.forename: Sascha
authors.initials: S
authors.lastname: Gutmann
mesh_terms: D003198:Computer Simulation; D003460:Crystallization / Q000379:methods; D016572:Cyclosporine / Q000737:chemistry* / Q000528:radiation effects*; D006859:Hydrogen / Q000737:chemistry* / Q000528:radiation effects*; D008956:Models, Chemical; D008958:Models, Molecular; D008968:Molecular Conformation / Q000528:radiation effects; D011829:Radiation Dosage
chemical_list: D006859:Hydrogen; D016572:Cyclosporine