Difference between revisions of "Part:BBa K1640020"

Revision as of 08:13, 18 September 2015

Sequence and Features

Overview

This biobrick contains one gene from the photosystem II complex of Chlamydomonas reinhardtii - psbA.

- psbA encodes D1, a subunit of the Photosystem II reaction centre.

This part was designed in conjunction with BBa_K1640024, and together they form operon 4 in our set of photosystem II operons:

Biology & Literature

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Protein information

References

Usage and Biology

PsbA encodes the Photosystem II reaction centre subunit D1. This product forms a heterodimer with D2, encoded by psbD, to form the Photosystem II reaction centre (Marder, Chapman, Telfer, Nixon, & Barber, 1987). The primary function of the D1/D2 reaction centre complex is to transfer electrons from the chlorophyll P680 to two quinones, designated QA and QB. To this end, D1 has functions both at the oxidation and reduction stages of the reaction.

D1 accepts electrons from P680, transferring it to QB. A tyrosine of D1 reduces the resulting P680 cation, resulting in a tyrosine radical. This radical acts as an oxidising agent for the oxidation of water through the oxygen evolving complex (OEC) of PSII (Ferreira, Iverson, Maghlaoui, Barber, & Iwata, 2004). In addition, this protein is vital to the assembly of both the OEC and QB within PSII. Site-directed mutagenesis studies have revealed an aspartate residue of D1 to be both structurally coupled to and involved in the assembly of the Mn cluster within the OEC (Chu, Debus, & Babcock, 2001; Nixon & Diner, 1992). Similarly, inhibition studies involving the binding of herbicides to D1 have revealed this protein to contain a niche for the binding of QB (Erickson et al., 1989; Jansen, Mattoo, Malkin, & Edelman, 1993).

Conclusion

PsbA encodes the reaction centre subunit D1 of Photosystem II, which forms a heterodimer with D2. This protein is involved in both the oxidation and reduction stages of the core PSII reaction, transferring electrons from P680 to QB, and acting as an oxidising agent for the oxidation of water through the oxygen evolution complex. After combining this part with psbD and psbC, and transfecting it into E. coli alongside psbMZHWK, psbTB, psbEJ and psbPQR, E. coli should express a functional, minimal Photosystem II complex derived from C. reinhardtii.