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Probing the smallest functional unit of the reaction center of Rhodospirillum rubrum G‐9 with proteinases
Author(s) -
Wiemken V.,
Bachofen R.
Publication year - 1984
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(84)80063-0
Subject(s) - rhodospirillum rubrum , protein subunit , photosynthetic reaction centre , sodium dodecyl sulfate , chemistry , polyacrylamide gel electrophoresis , gel electrophoresis , rhodospirillaceae , rhodospirillales , kinetics , biochemistry , stereochemistry , enzyme , photosynthesis , physics , quantum mechanics , gene
Reaction centers composed of subunits H, M, L (28 kDa, 24 kDa, 21 kDa) were isolated from Rhodospirillum rubrum G‐9 and subjected to progressive digestion with proteinase K. Photoactivity and spectral characteristics were retained as long as subunit L and a characteristic fragment (about 18 kDa) of another subunit, most probably of subunit M, remained intact. This was shown by sodium dodecyl sulfate polyacrylamide gel electrophoresis and by the finding of only two amino‐terminal sequences one of which was identical with that of subunit L. The rate of reduction of photooxidized P‐870 was decreased in the digested preparation of the reaction center as compared with the control but the kinetics of the reduction of photooxidized cytochrome c 2 was unchanged. It is inferred that subunit L and a part of subunit M form the smallest functional unit of the reaction center.