Thu, 07 Aug 2008 21:31:11 BST CiteULike: Tag psba http://www.citeulike.org/tag/psba CiteULike.org en-gb Copyright © 2004-2008 citeulike.org http://www.citeulike.org/user/llchristensen/article/2582808 <i>Plant Molecular Biology, Vol. 14, No. 1. (1 January 1990), pp. 81-92.</i><br /><br />The cyanobacterium Anabaena PCC 7120 contains a multigene family that encodes the D1 polypeptide of Photosystem II. This family consists of four members denoted psbAI-IV that are each unique but highly homologous. psbAII, III and IV are more closely related to each other than to psbAI. These three copies encode identical polypeptides that differ from the psbAI product by 21 amino acids. The transcription initiation site for psbAI has been mapped to 64–65 nucleotides upstream from the coding region. Primer extension assays performed with an oligonucleotide specific for psbAII, III and IV transcripts suggest that one or more of these genes is also expressed. Genomic mapping and chromosome walking experiments demonstrate that none of the four psbA copies is within 20 kbp of another member of the gene family. Characterization of a four-member psbA gene family from the cyanobacterium Anabaena PCC 7120 Jacqueline Vrba Stephanie Curtis doi:10.1007/BF00015657 Plant Molecular Biology, Vol. 14, No. 1. (1 January 1990), pp. 81-92. 2008-03-24T21:16:38-00:00 1990 Plant Molecular Biology 14 1 81 92 anabaena fam psba http://www.citeulike.org/user/llchristensen/article/2582804 <i>Biochimica et Biophysica Acta (BBA) - Bioenergetics, Vol. 1757, No. 1. (January 2006), pp. 47-56.</i><br /><br />Cyanobacteria cope with UVB induced photoinhibition of Photosystem II by regulating multiple psbA genes to boost the expression of D1 protein (in Synechocystis sp. PCC6803), or to exchange the constitutive D1:1 protein to an alternate D1:2 isoform (in Synechococcus sp. PCC7942). To define more general patterns of cyanobacterial psbA expression, we applied moderately photoinhibitory UVB to Anabaena sp. PCC7120 and tracked the expression of its five psbA genes. psbAI, encoding a D1:1 protein isoform characterized by a Gln130, represented the majority of the psbA transcript pool under control conditions. psbAI transcripts decreased upon UVB treatment but the total psbA transcript pool increased 3.5 fold within 90 min as a result of sharply increased psbAII, psbAIV and psbAIII transcripts encoding an alternate D1:2 protein isoform characterized by Glu130, similar to that of Synechococcus. Upon UVB treatment the relaxation of flash induced chlorophyll fluorescence showed a characteristic acceleration of a decay phase likely associated with the exchange from the D1:1 protein isoform encoded by psbAI to the alternate D1:2 isoform encoded by psbAIV, psbAII and psbAIII. Throughout the UVB treatment the divergent psbA0 made only a trace contribution to the total psbA transcript pool. This suggests a similarity to the divergent psbAI gene from Synechocystis, whose natural expression we demonstrate for the first time at a trace level similar to psbA0 in Anabaena. These trace-expressed psbA genes in two different cyanobacteria raise questions concerning the functions of these divergent genes. Cyanobacterial psbA families in Anabaena and Synechocystis encode trace, constitutive and UVB-induced D1 isoforms Cosmin Sicora Sarah Appleton Christopher Brown Jonathon Chung Jillian Chandler Amanda Cockshutt Imre Vass Douglas Campbell doi:10.1016/j.bbabio.2005.11.002 Biochimica et Biophysica Acta (BBA) - Bioenergetics, Vol. 1757, No. 1. (January 2006), pp. 47-56. 2008-03-24T21:13:44-00:00 2006 Biochimica et Biophysica Acta (BBA) - Bioenergetics 1757 1 47 56 fam psba uvb http://www.citeulike.org/user/jwm/article/2677195 <i>Biological chemistry (6 March 2008)</i><br /><br />Abstract In the cyanobacterium Thermosynechococcus elongatus BP-1, living in hot springs, the light environment directly regulates expression of genes that encode key components of the photosynthetic multi-subunit protein-pigment complex photosystem II (PSII). Light is not only essential as energy source to power photosynthesis, but leads to formation of aggressive radicals which induce severe damage of protein subunits and organic cofactors. Photosynthetic organisms developed several protection mechanisms against this photo-damage, one being the differential expression of genes coding for the reaction center subunit D1 in PSII. Testing the expression of the three different genes (psbAI, psbAII, psbAIII) coding for D1 in T. elongatus under culture conditions used for preparing the material used in crystallization of PSII showed that under these conditions only subunit PsbA1 is present. However, exposure to high-light intensity induced partial replacement of PsbA1 with PsbA3. Modeling of the variant amino acids of the three different D1 copies in the 3.0 A resolution crystal structure of PSII revealed that most of them are in direct vicinity to redox-active cofactors of the electron transfer chain. Possible structural and mechanistic consequences for electron transfer are discussed. Modeling of variant copies of subunit D1 in the structure of photosystem II from Thermosynechococcus elongatus. Bernhard Loll Matthias Broser Peter B Kós Jan Kern Jacek Biesiadka Imre Vass Wolfram Saenger Athina Zouni doi:10.1515/BC.2008.058 Biological chemistry (6 March 2008) 2008-04-16T08:56:58-00:00 2008 Biological chemistry 1431-6730 psba psii http://www.citeulike.org/user/jwm/article/2677196 <i>Biochimica et biophysica acta, Vol. 1777, No. 1. (January 2008), pp. 74-83.</i><br /><br />In Thermosynechococcus elongatus BP-1, which is the preferred organism in recent structural studies of PSII, three psbA and two psbD genes code for three D1 and one D2 protein isoforms, respectively. The regulation and function of these genes and protein products is largely unknown. Therefore, we used quantitative RT-PCR to follow changes in the mRNA level of the respective genes, in combination with biophysical measurements to detect changes in the electron transport activity of Photosystem II under exposure to different visible and UV light, and temperature conditions. In cells which are acclimated to 40 micromol m(-2)s(-1) growth light conditions at 40 degrees C the main populations of the psbA and psbD transcripts arise from the psbA1 and psbD1 genes, respectively. When the temperature is raised to 60 degrees C psbA1 becomes the single dominating psbA mRNA species. Upon exposure of the cells to 500 micromol m(-2)s(-1) intensity visible light psbA3 replaces psbA1 as the dominating psbA mRNA species, and psbD2 increases at the expense of psbD1. UV-B radiation also increases the abundance of psbA3, and psbD2 at the expense of psbA1 and psbD1, respectively. From the different extent of total D1 protein loss in the absence and presence of lincomycin it was estimated that the PsbA3 protein isoform replaces PsbA1 in about 65% of PSII centers after 2 h of high light acclimation. Under the conditions of different psbA transcript distributions chlorophyll fluorescence and thermoluminescence measurements were applied to monitor charge recombination characteristics of the S2Q(A)(-) and S2Q(B)(-) states. We obtained faster decay of flash-induced chlorophyll fluorescence in the presence of DCMU, as well as lower peak temperature of the Q and B thermoluminescence bands when PsbA3 replaced PsbA1 as the main D1 protein isoform. The relevance of dynamic changes in the abundance of psbA and psbD transcript levels, as well as D1 protein isoforms in the acclimation of T. elongatus to changing environmental conditions is discussed. Differential regulation of psbA and psbD gene expression, and the role of the different D1 protein copies in the cyanobacterium Thermosynechococcus elongatus BP-1. PB Kós Z Deák O Cheregi I Vass doi:10.1016/j.bbabio.2007.10.015 Biochimica et biophysica acta, Vol. 1777, No. 1. (January 2008), pp. 74-83. 2008-04-16T08:57:01-00:00 2008 Biochimica et biophysica acta 0006-3002 1777 1 74 83 psba psii http://www.citeulike.org/user/bluto/article/1281629 <i>Proc Natl Acad Sci U S A, Vol. 101, No. 30. (27 July 2004), pp. 11013-11018.</i><br /><br />Comparative genomics gives us a new window into phage-host interactions and their evolutionary implications. Here we report the presence of genes central to oxygenic photosynthesis in the genomes of three phages from two viral families (Myoviridae and Podoviridae) that infect the marine cyanobacterium Prochlorococcus. The genes that encode the photosystem II core reaction center protein D1 (psbA), and a high-light-inducible protein (HLIP) (hli) are present in all three genomes. Both myoviruses contain additional hli gene types, and one of them encodes the second photosystem II core reaction center protein D2 (psbD), whereas the other encodes the photosynthetic electron transport proteins plastocyanin (petE) and ferredoxin (petF). These uninterrupted, full-length genes are conserved in their amino acid sequence, suggesting that they encode functional proteins that may help maintain photosynthetic activity during infection. Phylogenetic analyses show that phage D1, D2, and HLIP proteins cluster with those from Prochlorococcus, indicating that they are of cyanobacterial origin. Their distribution among several Prochlorococcus clades further suggests that the genes encoding these proteins were transferred from host to phage multiple times. Phage HLIPs cluster with multicopy types found exclusively in Prochlorocococus, suggesting that phage may be mediating the expansion of the hli gene family by transferring these genes back to their hosts after a period of evolution in the phage. These gene transfers are likely to play a role in the fitness landscape of hosts and phages in the surface oceans. Transfer of photosynthesis genes to and from Prochlorococcus viruses. D Lindell MB Sullivan ZI Johnson AC Tolonen F Rohwer SW Chisholm doi:10.1073/pnas.0401526101 Proc Natl Acad Sci U S A, Vol. 101, No. 30. (27 July 2004), pp. 11013-11018. 2007-05-07T08:34:47-00:00 2004 Proc Natl Acad Sci U S A 0027-8424 101 30 11013 11018 hli micobiology myo photosynthesis podo prochlorococcus psba psbd http://www.citeulike.org/user/bluto/article/349561 <i>Nature (12 October 2005)</i> Photosynthesis genes in marine viruses yield proteins during host infection Debbie Lindell Jacob Jaffe Zackary Johnson George Church Sallie Chisholm doi:10.1038/nature04111 Nature (12 October 2005) 2005-10-12T23:41:54-00:00 2005 Nature 0028-0836 Nature Publishing Group micobiology photosynthesis podo prochlorococcus psba