title: Organization of photosystem I polypeptides examined by chemical cross-linking.
abstract: Photosystem I from the cyanobacterium Synechocystis sp. PCC 6803 was examined using the chemical cross-linkers glutaraldehyde and N-ethyl-1-3-[3-(dimethylamino)propyl]carbodiimide to investigate the organization of the polypeptide subunits. Thylakoid membranes and photosystem I, which was isolated by Triton X-100 fractionation, were treated with cross-linking reagents and were resolved using a Tricine/urea low-molecular-weight resolution gel system. Subunit-specific antibodies and western blotting analysis were used to identify the components of cross-linked species. These analyses identified glutaraldehyde-dependent cross-linking products composed of small amounts of PsaD and PsaC, PsaC and PsaE, and PsaE and PsaF. The novel cross-link between PsaE and PsaF was also observed following treatment with N-ethyl-1-3-[3-(dimethylamino)propyl]carbodiimide. These cross-linking results suggest a structural interaction between PsaE and PsaF and predict a transmembrane topology for PsaF.
authors.affiliation: Division of Biology, Kansas State University, Manhattan 66506-4901, USA.
authors.forename: T S
authors.initials: TS
authors.lastname: Armbrust
authors.forename: P R
authors.initials: PR
authors.lastname: Chitnis
authors.forename: J A
authors.initials: JA
authors.lastname: Guikema
mesh_terms: D003432:Cross-Linking Reagents / Q000737:chemistry*; D000458:Cyanobacteria / Q000737:chemistry* / Q000378:metabolism; D004579:Electron Transport; D004591:Electrophoresis, Polyacrylamide Gel; D005022:Ethyldimethylaminopropyl Carbodiimide / Q000031:analogs & derivatives / Q000737:chemistry; D005976:Glutaral / Q000737:chemistry; D008565:Membrane Proteins / Q000737:chemistry*; D010788:Photosynthesis / Q000502:physiology*; D045322:Photosynthetic Reaction Center Complex Proteins / Q000032:analysis / Q000737:chemistry* / Q000378:metabolism; D010940:Plant Proteins / Q000737:chemistry* / Q000378:metabolism
chemical_list: D003432:Cross-Linking Reagents; D008565:Membrane Proteins; D045322:Photosynthetic Reaction Center Complex Proteins; D010940:Plant Proteins; C021261:thylakoid polypeptides; C041829:1-ethyl-3-(3-(dimethylamino)propyl)carbodiimide methiodide; D005022:Ethyldimethylaminopropyl Carbodiimide; D005976:Glutaral