Photosystem II complex in vivo is a monomer.
Photosystem II (PS II) complexes are membrane protein complexes that are composed of >20 distinct subunit proteins. Similar to many other membrane protein complexes, two PS II complexes are believed to form a homo-dimer whose molecular mass is approximately 650 kDa. Contrary to this well known concept, we propose that the functional form of PS II in vivo is a monomer, based on the following observations. Deprivation of lipids caused the conversion of PS II from a monomeric form to a dimeric form. Only a monomeric PS II was detected in solubilized cyanobacterial and red algal thylakoids using blue-native polyacrylamide gel electrophoresis. Furthermore, energy transfer between PS II units, which was observed in the purified dimeric PS II, was not detected in vivo. Our proposal will lead to a re-evaluation of many crystallographic models of membrane protein complexes in terms of their oligomerization status.
Takahashi
Takeshi
T
Graduate School of Life Science, University of Hyogo, 3-2-1 Kohto, Kamigohri, Ako-gun, Hyogo 678-1297, Japan.
Inoue-Kashino
Natsuko
N
Ozawa
Shin-Ichiro
S
Takahashi
Yuichiro
Y
Kashino
Yasuhiro
Y
Satoh
Kazuhiko
K
D000458:Cyanobacteria / Q000235:genetics / Q000378:metabolism; D019281:Dimerization; D004579:Electron Transport; D004735:Energy Transfer; D008055:Lipids / Q000032:analysis; D008970:Molecular Weight; D010100:Oxygen / Q000378:metabolism; D010455:Peptides / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D045331:Photosystem I Protein Complex / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D045332:Photosystem II Protein Complex / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D011809:Quinones / Q000378:metabolism; D000461:Rhodophyta / Q000235:genetics / Q000378:metabolism; D013050:Spectrometry, Fluorescence; D046939:Synechocystis / Q000235:genetics / Q000378:metabolism; D020524:Thylakoids / Q000235:genetics / Q000378:metabolism
D008055:Lipids; D010455:Peptides; D045331:Photosystem I Protein Complex; D045332:Photosystem II Protein Complex; D011809:Quinones; D010100:Oxygen