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Stoichiometric association of extrinsic cytochrome c 550 and 12 kDa protein with a highly purified oxygen‐evolving photosystem II core complex from Synechococcus vulcanus
Author(s) -
Shen Jian-Ren,
Ikeuchi Masahiko,
Inoue Yorinao
Publication year - 1992
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(92)81235-e
Subject(s) - thylakoid , cytochrome , photosystem ii , protein subunit , synechococcus , cytochrome c , cyanobacteria , biochemistry , tris , chemistry , molecular mass , chloroplast , biology , photosynthesis , bacteria , mitochondrion , enzyme , genetics , gene
A highly purified, native photosystem II (PS II) core complex was isolated from thylakoids of Synechococcus vulcanus , a thermophilic cyanobacterium by lauryldimethylamine N ‐oxide (LDAO) and dodecylβ‐ d ‐maltoside solubilization. This native PS II core complex contained, in addition to the proteins that have been well characterized in the core complex previously purified by LDAO and Triton X‐100, two more extrinsic proteins with apparent molecular weights of 17 and 12 kDa. These two proteins were associated with the core complex in stoichiometric amounts and could be released by treatment with 1 M CaCl 2 or 1 M alkaline Tris but not by 2 M NaCl or low‐glycerol treatment, indicating that they are the real components of Ps II of this cyanobacterium. N‐Terminal sequencing revealed that the 17 and 12 kDa proteins correspond to the apoprotein of cytochrome c 550 , a low potential c ‐type cytochrome, and the 9 kDa extrinsic protein previously found in a partially purified PS II preparation from Phormidium laminosum , respectively. In spite of retention of these two extrinsic proteins, no homologues of higher plant 23 and 17 kDa extrinsic proteins could be detected in this cyanobacterial PS II core complex.