Efficient phage-mediated pigment biosynthesis in oceanic cyanabacteria
Efficient phage-mediated pigment biosynthesis in oceanic cyanabacteria
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DOI：
10.1016/j.cub.2008.02.067
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发表时间：
2008-03-25
期刊：
影响因子：
9.2
通讯作者：
Frankenberg-Dinkel, Nicole
中科院分区：
文献类型：
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作者：
Dammeyer, Thorben;Bagby, Sarah C.;Frankenberg-Dinkel, Nicole
虽然海洋蓝细菌原绿球藻利用叶绿素天线[1-3]而不是典型的蓝细菌藻胆体来获得光，但一些菌株表达的基因是祖先聚球藻藻胆体的残余物[4]。类似地，一些原绿球藻噬藻体，通常携带光合作用相关基因[5]，也携带藻胆体色素生物合成基因的同源物[6，7]。在这里，我们研究了两种感染丰富原绿球藻菌株的噬藻体中的四种这样的基因[8]：肌病毒P-SSM 2中的血红素加氧酶（hol）、15，16-二氢胆绿素：铁氧还蛋白氧化还原酶（pebA）、铁氧还蛋白（petF）的同源物，以及肌病毒P-SSM 4中的藻蓝胆素：铁氧还蛋白氧化还原酶（pcyA）同源物。我们表明，噬菌体同系物模仿各自的主机活动，除了分歧的噬菌体PebA同系物。在这种情况下，噬菌体PebA单独催化未感染宿主细胞需要两种连续酶PebA和PebB的反应。因此，我们将噬菌体酶藻红胆素合酶（PebS）重新命名。该基因和P-SSM 2编码的其他色素生物合成基因（petF和hol）在感染期间被转录，表明它们可以改善噬菌体适应性。对全球海洋宏基因组的分析表明，PcyA和Hol都存在于蓝藻和蓝藻中，而新的PebS编码基因是蓝藻独有的。
Although the oceanic cyanobacterium Prochlorococcus harvests light with a chlorophyll antenna [1-3] rather than with the phycobilisomes that are typical of cyanobacteria, some strains express genes that are remnants of the ancestral Synechococcus phycobilisomes [4]. Similarly, some Prochlorococcus cyanophages, which often harbor photosynthesis-related genes [5], also carry homologs of phycobilisome pigment biosynthesis genes [6, 7]. Here, we investigate four such genes in two cyanophages that both infect abundant Prochlorococcus strains [8]: homologs of heme oxygenase (hol), 15,16-dihydrobiliverdin:ferredoxin oxidoreductase (pebA), ferredoxin (petF) in the myovirus P-SSM2, and a phycocyanobilin:ferredoxin oxidoreductase (pcyA) homolog in the myovirus P-SSM4. We demonstrate that the phage homologs mimic the respective host activities, with the exception of the divergent phage PebA homolog. In this case, the phage PebA single-handedly catalyzes a reaction for which uninfected host cells require two consecutive enzymes, PebA and PebB. We thus renamed the phage enzyme phycoerythrobilin synthase (PebS). This gene, and other pigment biosynthesis genes encoded by P-SSM2 (petF and hol), are transcribed during infection, suggesting that they can improve phage fitness. Analyses of global ocean metagenomes show that PcyA and Hol occur in both cyanobacteria and their phages, whereas the novel PebS-encoding gene is exclusive to phages.