title: X-ray induced reduction of the crystal of high-molecular-weight cytochrome c revealed by microspectrophotometry.
abstract: The crystal structures of high-molecular-weight cytochrome c (HMC) from Desulfovibrio vulgaris Hildenborough in the transient and reduced states have been determined at 2.8 A resolution. An absorption spectrum measured with microspectrophotometer indicated that about 86% of the hemes were reduced after 45 min irradiation of the X-ray beam. Further exposure for 90 min did not significantly change the spectrum. These results suggest that HMC in the crystalline state is easily reduced by illumination of the X-ray beam from synchrotron radiation.
authors.affiliation: Himeji Institute of Technology, 3-2-1 Koto, Kamigori-cho, Ako-gun, Hyogo 678-1297, Japan.
authors.forename: Midori
authors.initials: M
authors.lastname: Sato
authors.forename: Naoki
authors.initials: N
authors.lastname: Shibata
authors.forename: Yukio
authors.initials: Y
authors.lastname: Morimoto
authors.forename: Yuki
authors.initials: Y
authors.lastname: Takayama
authors.forename: Kiyoshi
authors.initials: K
authors.lastname: Ozawa
authors.forename: Hideo
authors.initials: H
authors.lastname: Akutsu
authors.forename: Yoshiki
authors.initials: Y
authors.lastname: Higuchi
authors.forename: Noritake
authors.initials: N
authors.lastname: Yasuoka
mesh_terms: D003198:Computer Simulation; D045304:Cytochromes c / Q000737:chemistry / Q000528:radiation effects* / Q000648:ultrastructure*; D016969:Desulfovibrio vulgaris / Q000737:chemistry* / Q000201:enzymology; D015591:Microspectrophotometry / Q000379:methods*; D008958:Models, Molecular; D011487:Protein Conformation / Q000528:radiation effects*; D017356:Synchrotrons; D014961:X-Ray Diffraction; D014965:X-Rays
chemical_list: D045304:Cytochromes c