A novel protein in Photosystem II of a diatom Chaetoceros gracilis is one of the extrinsic proteins located on lumenal side and directly associates with PSII core components.
The gene encoding a novel extrinsic protein (Psb31) found in Photosystem II (PSII) of a diatom, Chaetoceros gracilis, was cloned and sequenced. The deduced protein contained three characteristic leader sequences targeted for chloroplast endoplasmic reticulum membrane, chloroplast envelope membrane and thylakoid membrane, indicating that Psb31 is encoded in the nuclear genome and constitutes one of the extrinsic proteins located on the lumenal side. Homologous genes were found in a red alga and chromophytic algae but not in other organisms. Genes encoding the other four extrinsic proteins in C. gracilis PSII were also cloned and sequenced, and their leader sequences were characterized and compared. To search for the nearest neighbor relationship between Psb31 and the other PSII components, we crosslinked the PSII particles with the water-soluble carbodiimide, 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide, and found that Psb31 directly associates with PSII core components through electrostatic interaction, suggesting that the novel Psb31 protein is one of the extrinsic proteins constituting the functional oxygen-evolving complex of C. gracilis PSII.
Department of Integrated Sciences in Physics and Biology, College of Humanities and Sciences, Nihon University, Sakurajosui 3-25-40, Setagaya-ku, Tokyo 156-8850, Japan.
Akinori
A
Okumura
Ryo
R
Nagao
Takehiro
T
Suzuki
Satoshi
S
Yamagoe
Masako
M
Iwai
Katsuyoshi
K
Nakazato
Isao
I
Enami
D020418:Algal Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D000595:Amino Acid Sequence; D001483:Base Sequence; D003001:Cloning, Molecular; D003432:Cross-Linking Reagents / Q000494:pharmacology; D017377:Diatoms / Q000187:drug effects / Q000378:metabolism*; D005022:Ethyldimethylaminopropyl Carbodiimide / Q000494:pharmacology; D008969:Molecular Sequence Data; D010455:Peptides / Q000378:metabolism; D045332:Photosystem II Protein Complex / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D010802:Phylogeny; D011485:Protein Binding / Q000187:drug effects; D021382:Protein Sorting Signals; D017422:Sequence Analysis, DNA
D020418:Algal Proteins; D003432:Cross-Linking Reagents; D010455:Peptides; D045332:Photosystem II Protein Complex; D021382:Protein Sorting Signals; D005022:Ethyldimethylaminopropyl Carbodiimide