title: Cloning, expression of the psbU gene, and functional studies of the recombinant 12-kDa protein of photosystem II from a red alga Cyanidium caldarium.
abstract: The encoding extrinsic 12-kDa protein of oxygen-evolving PS II complex from a red alga, Cyanidium caldarium, was cloned and sequenced by means of PCR and a rapid amplification of cDNA ends (RACE) procedure. The gene encodes a putative polypeptide of 154 amino acids with a calculated molecular mass of 16,714 Da. The full sequence of the protein includes two characteristic transit peptides, one for transfer across the chloroplast envelope and another for targeting into the thylakoid lumen. This indicates that the protein is encoded in the nuclear genome. The mature protein consists of 93 amino acids with a calculated molecular mass of 10,513 Da. The cloned gene was successfully expressed in Escherichia coli and the resulting protein was purified, reconstituted to CaCl2-washed PS II complex together with the other extrinsic proteins of 33 and 20 kDa and cyt c-550. The recombinant 12-kDa protein bound completely with the PSII complex, which resulted in a restoration of oxygen evolution equal to the level achieved by binding of the native 12-kDa protein.
authors.affiliation: Department of Biology, Faculty of Science, Science University of Tokyo, Tokyo, Kagurazaka, Shinjuku-ku, 162-8601, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Ohta
authors.forename: A
authors.initials: A
authors.lastname: Okumura
authors.forename: S
authors.initials: S
authors.lastname: Okuyama
authors.forename: A
authors.initials: A
authors.lastname: Akiyama
authors.forename: M
authors.initials: M
authors.lastname: Iwai
authors.forename: S
authors.initials: S
authors.lastname: Yoshihara
authors.forename: J R
authors.initials: JR
authors.lastname: Shen
authors.forename: M
authors.initials: M
authors.lastname: Kamo
authors.forename: I
authors.initials: I
authors.lastname: Enami
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins; D001483:Base Sequence; D002122:Calcium Chloride / Q000494:pharmacology; D003001:Cloning, Molecular; D015870:Gene Expression; D008969:Molecular Sequence Data; D010100:Oxygen / Q000378:metabolism; D045322:Photosynthetic Reaction Center Complex Proteins / Q000737:chemistry* / Q000235:genetics* / Q000378:metabolism*; D045332:Photosystem II Protein Complex; D011994:Recombinant Proteins / Q000737:chemistry; D000461:Rhodophyta / Q000737:chemistry*; D017386:Sequence Homology, Amino Acid
chemical_list: D001426:Bacterial Proteins; D045322:Photosynthetic Reaction Center Complex Proteins; D045332:Photosystem II Protein Complex; C107126:PsbU protein, Synechocystis; D011994:Recombinant Proteins; D002122:Calcium Chloride; D010100:Oxygen