Difference between revisions of "Part:BBa K1640008"

Revision as of 03:59, 15 September 2015

psbMZH

PsbM gene from Chlamydomonas reinhardtii Encodes psbM, a Photosystem II core complex subunit PsbZ gene from Chlamydomonas reinhardtii Encodes psbZ, a stabilising protein for the Photosystem II/Light Harvesting Complex II supercomplex PsbH gene from Chlamydomonas reinhardtii Encodes psbH, a Photosystem II core complex subunit

Usage and Biology

PsbM encodes a highly hydrophobic protein, psbM, with a single, membrane spanning α-helix located at the monomer-monomer interface of PSII (Ferreira, Iverson, Maghlaoui, Barber, & Iwata, 2004). This proteins acts to stabilise the dimerization of PSII. While not a necessary factor for PSII biosynthesis, its absence weakens the dimer interconnection of the core complex, and may impair PSII repair (Umate et al., 2007). Deletion studies of this gene have shown a 28% decrease in successfully assembled PSII centres (Bentley, Luo, Dilbeck, Burnap, & Eaton-Rye, 2008).

PsbZ, also referred to as ycf9, is a highly conserved gene amongst photosynthetic species, encoding a two transmembrane helix protein, psbZ (Ferreira et al., 2004). PsbZ is found at the interface between PSII and light harvesting complex II (LHCII). (Minagawa & Takahashi, 2004). Deletion studies of psbZ have resulted in decreased stability of the PSII-LHCII supercomplex, suggesting this protein is involved in anchoring the two complexes (Swiatek et al., 2001).

PsbH encodes a low molecular weight PSII subunit, psbH, containing multiple phosphorylation sites (Vener, Harms, Sussman, & Vierstra, 2001). Deletion studies of this gene across multiple species have shown different effects. In Synechocystis sp., a slower growth rate, higher light sensitivity, and impaired electron transport from QA to QB has been observed (Mayes et al., 1993). In addition, the deletion of psbH has been observed to both destabilize the PSII complex, and impair the binding of bicarbonate to the complex (Komenda, Lupínková, & Kopecký, 2002), and in Chlamydomonas reinhardtii, eliminate the formation of the PSII complex, revealing psbH as a vital gene for the synthesis of Photosystem II (Summer, Schmid, Bruns, & Schmidt, 1997).

Sequence and Features

Conclusions

PsbMZH encodes three, low molecular weight subunits of Photosystem II (PSII), responsible for both stabilizing the PSII core monomer and anchoring Light Harvesting Complex II (LHCII) to PSII. After combining this part with psbWK, and transfecting it into E. coli alongside psbDCA, psbTB, psbEJ and psbPQR, E. coli should express a functional, minimal Photosystem II complex derived from C. reinhardtii.