Rubredoxin A Explained

Rubredoxin A (RubA) is a protein conserved across all studied oxygenic photoautotrophs.^[1]

Structure

As of March 2015 there was no crystal structure of RubA although a structure of the homologous protein from a cryptomonad was determined using NMR.^[2] Investigation of the gene however indicates that it differs from other known rubredoxins in being bound to the thylakoid membrane via a C-terminal transmembrane helix.^{[1] [3] [4]}

Function

An investigation of Guillardia theta noted that RubA had a similar distribution to Photosystem II (PSII) and immunological experiments indicated the presence of RubA in PSII complexes isolated from Spinacia oleracea.^[3] In Synechocystis sp. PCC 6803 it has been demonstrated that the insertion of an antibiotic cassette into the rubA gene results in a marked decrease in the amount of PSII present,^[1] while the same mutation within Chlamydomonas reinhardtii and in Arabidopsis thaliana results in a total absence of PSII.^[1]

Conversely, another study performed in Synechococcus sp. PCC 7002 indicated that mutation of the rubA gene interfered with iron-sulphur cluster assembly in Photosystem I (PSI), rather than affecting PSII.^{[4] [5]}

Notes and References

1. Calderon, R. H., García-Cerdán, J. G., Malnoë, A., Cook, R., Russell, J. J., Gaw, C., Dent, R. M., de Vitry, C. and Niyogi, K. K. . A Conserved Rubredoxin Is Necessary for Photosystem II Accumulation in Diverse Oxygenic Photoautotrophs . The Journal of Biological Chemistry . 288 . 26688–26696 . July 2013 . 37 . 10.1074/jbc.M113.487629 . 23900844 . 3772215. free .
2. Schweimer, K., Hoffmann, S., Wastl, J., Maier, U.G., Rösch, P., and Sticht H. . Solution structure of a zinc substituted eukaryotic rubredoxin from the cryptomonad alga "Guillardia theta". Protein Science . 2000. 9 . 8. 1474–1486 . 10.1110/ps.9.8.1474 . 10975569 . 2144721.
3. Wastl, J., Duin, E. C., Iuzzolino, L., Dörner, W., Link. T., Dau, H., Lingelbach, K. and Maier U. G. . Eukaryotically Encoded and Chloroplast-located Rubredoxin Is Associated with Photosystem II . The Journal of Biological Chemistry . 2000 . 275 . 39 . 30058–30068 . 10.1074/jbc.M004629200 . 10878021. free .
4. Shen, G., Zhao, J., Reimer, S. K., Antonkine, M. L., Cai, Q., Weiland, S. M., Golbeck, J. H. and Bryant, D. A. . Assembly of Photosystem II: I. Inactivation of The rubA Gene Encoding A Membrane-Associated Rubredoxin In The Cyanobacterium Synechococcus sp. PCC 7002 Causes A Loss of Photosystem I Activity . The Journal of Biological Chemistry . 2002 . 277 . 23 . 20343–20354 . 10.1074/jbc.M201103200 . 11914373. free.
5. Shen, G., Antonkine, M. L., van der Est, A., Vassiliev, I. R., Brettel, K., Bittl, R., Zech, S. G., Zhao, J., Stehlik, D., Bryant, D. A. and Golbeck, J. H. . Assembly of Photosystem I: II. Rubredoxin Is Required for the Assembly of Fx in Synechococcus sp. PCC 7002 As Shown by Optical and EPR Spectroscopy . The Journal of Biological Chemistry . 2002 . 277 . 23 . 20355–20366 . 10.1074/jbc.M201104200. 11914374 . free .