Association of small CAB-like proteins (SCPs) of Synechocystis sp. PCC 6803 with Photosystem II.
The cyanobacterial small CAB-like proteins (SCPs) are one-helix proteins with compelling similarity to the first and third transmembrane helix of proteins belonging to the CAB family of light-harvesting complex proteins in plants. The SCP proteins are transiently expressed at high light intensity and other stress conditions but their exact function remains largely unknown. Recently we showed association of ScpD with light-stressed, monomeric Photosystem II in Synechocystis sp. PCC 6803 (Yao et al. J Biol Chem 282:267-276, 2007). Here we show that ScpB associates with Photosystem II at normal growth conditions. Moreover, upon introduction of a construct into Synechocystis so that ScpB is expressed continuously under normal growth conditions, ScpE was detected under non-stressed conditions as well, and was copurified with tagged ScpB and Photosystem II. We also report on a one-helix protein, Slr1544, that is somewhat similar to the SCPs and whose gene is cotranscribed with that of ScpD; Slr1544 is another member of the extended light-harvesting-like (Lil) protein family, and we propose to name it LilA.
Kufryk
Galyna
G
Department of Chemistry, Umeå University, Umeå, 901 87, Sweden.
Hernandez-Prieto
Miguel A
MA
Kieselbach
Thomas
T
Miranda
Helder
H
Vermaas
Wim
W
Funk
Christiane
C
D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry / Q000378:metabolism*; D001483:Base Sequence; D015152:Blotting, Northern; D015153:Blotting, Western; D017931:DNA Primers; D004591:Electrophoresis, Polyacrylamide Gel; D017343:Genes, Plant; D008969:Molecular Sequence Data; D045332:Photosystem II Protein Complex / Q000378:metabolism*; D011485:Protein Binding; D018749:RNA, Plant / Q000235:genetics; D017386:Sequence Homology, Amino Acid; D046939:Synechocystis / Q000235:genetics / Q000378:metabolism*; D053719:Tandem Mass Spectrometry
D001426:Bacterial Proteins; D017931:DNA Primers; D045332:Photosystem II Protein Complex; D018749:RNA, Plant