User:R. Jeremy Johnson/Sandbox 1: Difference between revisions

This structure of Photosystem II was crystallized from the cyanobacteria, ''Thermosynechococcus elongatus'', at 3.0Å <ref>Loll, B., Kern, J., Saenger, W., Zouni, A., Biesiadka, J., "Towards complete cofactor arrangement in the 3.0 A resolution structure of photosystem II."  Nature, Dec 15, 2005, 438(7070), 1040-4.  PMID:[http://www.ncbi.nlm.nih.gov/pubmed/16355230 16355230]</ref> and at 3.50 Å <ref>Ferreira, K.N., Iverson, T.M., Maghlaoui, K., Barber, J., Iwata, S.  "Architecture of the photosynthetic oxygen-evolving center."  Science, March 19, 2004, 303 (5665), 1831-8.  PMID:[http://www.ncbi.nlm.nih.gov/pubmed/14764885 14764885]</ref>. PDB codes are [[2axt]] and [[1s5l]], respectively.  Cyanobacteria and plants both contain Photosystem II while photosynthetic bacteria contain the bacterial reaction center.  This photosynthetic protein complex is associated with a variety of functional ligands. It is a <scene name='Photosystem_II/Psii_dimer/1'>dimer</scene> composed mainly of alpha-helices.  Nineteen <scene name='Photosystem_II/Protein_only/1'>subunits</scene> are in each monomer, with multiple extrinsic subunits associated with the oxygen evolving complex missing from this crystallization.  Photosystem II is a membrane bound protein complex that in plants is associated with the thylakoid membrane of chloroplasts.  <scene name='Photosystem_II/Hydrophobic_polar/1'>Polar and hydrophobic</scene> regions correlate with membrane associated nature of the protein.  '''<FONT COLOR="#616D7E">Hydrophobic</FONT>''' helices make up the transmembranal portion, while '''<FONT COLOR="#C031C7">polar</FONT>''' residues are concentrated externally on either side of the membrane.

==Basic Structure==