High impact information on psbE

• We used potassium thiocyanate to separate PSII into subcore complexes, including the D1/D2/cytochrome b559 reaction center complex, CP47, and CP43, and we found that PsbK co-purifies with one of the core antenna complexes, CP43, during ion exchange chromatography [1].
• The role of cytochrome b-559 in the photosystem two (PSII) complex has been investigated through the construction of a psbE null mutant by transformation of the chloroplast genome of the green alga Chlamydomonas reinhardtii [2].
• Our results provide evidence for a role for cytochrome b-559 in the early steps of assembly of the PSII complex, possibly as a redox-controlled nucleation factor that determines the level of PSII within the thylakoid membrane [2].
• Four small subunits were identified by N-terminal sequencing, namely a 6.1-kDa nuclear-encoded subunit and three chloroplast-encoded subunits homologous to psbE, psbK, and psbM gene products [3].
• Mössbauer studies of the non-heme iron and cytochrome b559 in a Chlamydomonas reinhardtii PSI- mutant and their interactions with alpha-tocopherol quinone [4].

Biological context of psbE

• An unusual organization of the genes encoding cytochrome b559 in Chlamydomonas reinhardtii: psbE and psbF genes are separately transcribed from different regions of the plastid chromosome [5].
• We have determined the nucleotide sequences of the psbE and psbF genes, which encode the alpha and beta subunits, respectively, of cytochrome b-559, from the chloroplast genome of the green alga Chlamydomonas reinhardtii [6].

Anatomical context of psbE

• The predicted amino-terminal domains of both polypeptides are more basic than those of other organisms, and the sequence of the psbE gene product indicates a departure from the 'positive-inside' rule for the insertion of proteins in the thylakoid membrane [5].
• We have cloned and sequenced the psbE and psbF genes of the Chlamydomonas reinhardtii plastid genome [5].

Associations of psbE with chemical compounds

• But 3-(3,4-dichlorophenyl)-1,1-dimethylurea-insensitive Photosystem I-dependent photooxidations of cytochrome b-559 occurred also in the wild type [7].
• Picric acid, antimycin A and tetraphenylboron were also able to induce cytochrome b-559 photooxidation in chloroplast fragments, but not in whole cells [7].

Other interactions of psbE

• Northern blot analysis demonstrated that psbE is transcribed into a 0.3 kb mRNA, while transcription of psbF and psbL genes results in a 0.9 kb transcript [5].
• Upstream of the psbE gene, a trnM gene is located which encodes an elongator tRNA(Met) molecule [6].

Analytical, diagnostic and therapeutic context of psbE

• Spin and valence states of the non-heme iron and the heme iron of cytochrome b559, as well as their interactions with alpha-tocopherol quinone (alpha-TQ) in photosystem II (PSII) thylakoid membranes prepared from the Chlamydomonas reinhardtii PSI- mutant have been studied using Mössbauer spectroscopy [4].

References