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The transverse membrane orientation of the light‐harvesting and reaction centre polypeptides of Rhodopseudomonas capsulata , investigated by surface iodination
Author(s) -
Peters Jürgen D.,
Drews Gerhart
Publication year - 1983
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(83)81048-5
Subject(s) - membrane , polyacrylamide gel electrophoresis , chemistry , reagent , gel electrophoresis , photosynthetic reaction centre , chromatophore , sodium , rhodopseudomonas , electrophoresis , biochemistry , chromatography , biophysics , photosynthesis , biology , organic chemistry , enzyme , fishery
The transverse orientation of photosynthetic polypeptides in the membrane of Rhodopseudomonas capsulata was investigated using surface radioiodination of chromatophores and spheroplasts with the reagent 1,3,4,6‐tetrachloro‐3α, 6α‐diphenylglycoluril. Native pigment‐protein complexes were isolated by Triton X‐100‐polyacrylamide gel electrophoresis to identify and distinguish polypeptides not separated by sodium dodecylsulphate‐polyacrylamide gel electrophoresis. The two antenna light‐harvesting complexes were found to be asymmetrically oriented with polypeptides 14 kDa and 8 kDa of complex B800‐850 and 12 kDa of B870 being exposed on either membrane surface. Subunits H and M of the photochemical reaction centre, and probably L, span the membrane.