title: Use of Protein Cross-Linking and Radiolytic Labeling To Elucidate the Structure of PsbO within Higher-Plant Photosystem II.
abstract: We have used protein cross-linking with the zero-length cross-linker 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide, and radiolytic footprinting coupled with high-resolution tandem mass spectrometry, to examine the structure of higher-plant PsbO when it is bound to Photosystem II. Twenty intramolecular cross-linked residue pairs were identified. On the basis of this cross-linking data, spinach PsbO was modeled using the Thermosynechococcus vulcanus PsbO structure as a template, with the cross-linking distance constraints incorporated using the MODELLER program. Our model of higher-plant PsbO identifies several differences between the spinach and cyanobacterial proteins. The N-terminal region is particularly interesting, as this region has been suggested to be important for oxygen evolution and for the specific binding of PsbO to Photosystem II. Additionally, using radiolytic mapping, we have identified regions on spinach PsbO that are shielded from the bulk solvent. These domains may represent regions on PsbO that interact with other components, as yet unidentified, of the photosystem.
authors.affiliation: Division of Biochemistry and Molecular Biology, Department of Biological Sciences, Louisiana State University , Baton Rouge, Louisiana 70803, United States.
authors.forename: Manjula P
authors.initials: MP
authors.lastname: Mummadisetti
authors.affiliation: Division of Biochemistry and Molecular Biology, Department of Biological Sciences, Louisiana State University , Baton Rouge, Louisiana 70803, United States.
authors.forename: Laurie K
authors.initials: LK
authors.lastname: Frankel
authors.affiliation: The J. Bennett Johnston, Sr. Center for Advanced Microstructures & Devices, Louisiana State University , Baton Rouge, Louisiana 70806, United States.
authors.forename: Henry D
authors.initials: HD
authors.lastname: Bellamy
authors.affiliation: The Rieveschl Laboratories for Mass Spectrometry, Department of Chemistry, University of Cincinnati , Cincinnati, Ohio 45221, United States.
authors.forename: Larry
authors.initials: L
authors.lastname: Sallans
authors.affiliation: The J. Bennett Johnston, Sr. Center for Advanced Microstructures & Devices, Louisiana State University , Baton Rouge, Louisiana 70806, United States.
authors.forename: Jost S
authors.initials: JS
authors.lastname: Goettert
authors.affiliation: Division of Biochemistry and Molecular Biology, Department of Biological Sciences, Louisiana State University , Baton Rouge, Louisiana 70803, United States.
authors.forename: Michal
authors.initials: M
authors.lastname: Brylinski
authors.affiliation: Division of Biochemistry and Molecular Biology, Department of Biological Sciences, Louisiana State University , Baton Rouge, Louisiana 70803, United States.
authors.forename: Terry M
authors.initials: TM
authors.lastname: Bricker
mesh_terms: D000595:Amino Acid Sequence; D003432:Cross-Linking Reagents; D018360:Crystallography, X-Ray; D000458:Cyanobacteria / Q000254:growth & development / Q000378:metabolism*; D013058:Mass Spectrometry; D008958:Models, Molecular; D045332:Photosystem II Protein Complex / Q000737:chemistry* / Q000378:metabolism; D010940:Plant Proteins / Q000737:chemistry* / Q000378:metabolism; D011485:Protein Binding; D011487:Protein Conformation; D023302:Protein Footprinting; D011675:Pulse Radiolysis; D017386:Sequence Homology, Amino Acid; D018724:Spinacia oleracea / Q000254:growth & development / Q000378:metabolism*; D017356:Synchrotrons
chemical_list: D003432:Cross-Linking Reagents; D045332:Photosystem II Protein Complex; D010940:Plant Proteins; C052389:oxygen-evolving enhancer protein 1, plant