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Identification of psb I and psb L gene products in cyanobacterial photosystem II reaction center preparation
Author(s) -
Ikeuchi Masahiko,
Koike Hiroyuki,
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)81446-2
Subject(s) - photosynthetic reaction centre , photosystem ii , protein subunit , molecular mass , chloroplast , biology , chemistry , gene , cytochrome c , biochemistry , microbiology and biotechnology , photosynthesis , enzyme , mitochondrion
Photosystem II (PS II) reaction center complex of higher plants was revealed to contain a new low‐molecular‐mass component of 4.8 kDa encoded by a chloroplast gene, psb I [(1988) FEBS Lett. 241, 99–104], in addition to D1, D2 and two subunits of cytochrome b ‐559. Here we isolated a PS II reaction center complex from the thermophilic cyanobacterium, Synechococcus vulcanus , by column chromatography using Triton X‐100 and urea, and attempted to identify the same gene product. SDS gel electrophoresis of the cyanobacterial reaction center complex resolved three protein bands of 8, 5.4 and 5 kDa in addition to D1, D2 and a partially remaining 47 kDa protein. N‐terminal sequencing revealed that the 5 kDa band consisted of two components: one, having an open N‐terminus, was homologous to the psb L gene product of higher plants, and the other, having a blocked N‐terminus, was homologous to the psb I gene product of higher plants. The 8 kDa and 5.4 kDa were the large and small subunits of cytochrome b ‐559, respectively. Based on these results, we conclude that the subunit structure of cyanobacterial PS II reaction center complex is essentially the same as that of higher plants except that the cyanobacterial psb L product is more tightly associated with the reaction center.