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Low‐molecular‐mass proteins in cyanobacterial photosystem II: Identification of psb H and psb K gene products by N‐terminal sequencing
Author(s) -
Koike Hiroyuki,
Mamada Kaoru,
Ikeuchi Masahiko,
Inoue Yorinao
Publication year - 1989
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(89)80570-8
Subject(s) - molecular mass , biochemistry , biology , protein subunit , photosystem ii , peptide sequence , gel electrophoresis , phosphoprotein , polyacrylamide gel electrophoresis , gene product , microbiology and biotechnology , gene , chemistry , gene expression , photosynthesis , enzyme
The O 2 ‐evolving photosystem II core complex was isolated from a thermophilic cyanobacterium, Synechococcus vulcanus Copeland. Analysis by SDS‐polyacrylamide gel electrophoresis revealed that the complex contained at least seven low‐molecular‐mass proteins in addition to the well characterized CP47 apoprotein, CP43 apoprotein, 33 kDa extrinsic protein, D1 protein, D2 protein and large subunit of cytochrome b ‐559. The separation profiles of these low‐molecular‐mass proteins were very similar between cyanobacterial and higher plant PS II. N‐terminal sequences of the 6.5 kDa and 3.9 kDa proteins of cyanobacterial core complex were determined after blotting to a polyvinylidene difluoride membrane. The sequence of the 6.5 kDa protein showed high homology with an internal sequence of plant psb H gene product, so‐called 10 kDa phosphoprotein, but did not conserve the Thr residue which is specifically phosphorylated in plants. The sequence of the 3.9 kDa protein corresponded to the K protein of higher plants (mature form of psb K gene product). These results indicate that the products of both psb H and psb K genes are present in cyanobacterial PS II as well as being associated with the O 2 ‐evolving core complex.