Low-molecular-mass polypeptide components of a photosystem II preparation from the thermophilic cyanobacterium Thermosynechococcus vulcanus.
Using a recently introduced electrophoresis system [Kashino et al. (2001) Electrophoresis 22: 1004], components of low-molecular-mass polypeptides were analyzed in detail in photosystem II (PSII) complexes isolated from a thermophilic cyanobacterium, Thermosynechococcus vulcanus (formerly, Synechococcus vulcanus). PsbE, the large subunit polypeptide of cytochrome b(559), showed an apparent molecular mass much lower than the expected one. The unusually large mobility could be attributed to the large intrinsic net electronic charge. All other Coomassie-stained polypeptides were identified by N-terminal sequencing. In addition to the well-known cyanobacterial PSII polypeptides, such as PsbE, F, H, I, L, M, U, V and X, the presence of PsbY, PsbZ and Psb27 was also confirmed in the isolated PSII complexes. Furthermore, the whole amino acid sequence was determined for the polypeptide which was known as PsbN. The whole amino acid sequence revealed that this polypeptide was identical to PsbTc which has been found in higher plants and green algae. These results strongly suggest that PsbN is not a member of the PSII complex. It is also shown that cyanobacteria have cytochrome b(559) in the high potential form as in higher plants.
Kashino
Yasuhiro
Y
Himeji Institute of Technology, Faculty of Science, Harima Science Garden City, Hyogo, 678-1297 Japan. kashino@sci.himeji-tech.ac.jp
Koike
Hiroyuki
H
Yoshio
Maki
M
Egashira
Hirokazu
H
Ikeuchi
Masahiko
M
Pakrasi
Himadri B
HB
Satoh
Kazuhiko
K
D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D003001:Cloning, Molecular; D000458:Cyanobacteria / Q000235:genetics / Q000378:metabolism*; D003573:Cytochrome b Group / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D008970:Molecular Weight; D010788:Photosynthesis / Q000235:genetics / Q000502:physiology; D045322:Photosynthetic Reaction Center Complex Proteins / Q000235:genetics / Q000378:metabolism*; D045332:Photosystem II Protein Complex; D017386:Sequence Homology, Amino Acid; D013696:Temperature; D020524:Thylakoids / Q000378:metabolism
D001426:Bacterial Proteins; D003573:Cytochrome b Group; D045322:Photosynthetic Reaction Center Complex Proteins; D045332:Photosystem II Protein Complex; C019313:cytochrome b559