Cannon Gordon C, Heinhorst Sabine, Bradburne Christopher E, Shively Jessup M
Department of Chemistry and Biochemistry, University of Southern Mississippi, Hattiesburg, MS 39406, USA.Corresponding author; email:
Department of Chemistry and Biochemistry, University of Southern Mississippi, Hattiesburg, MS 39406, USA.
Funct Plant Biol. 2002 Apr;29(3):175-182. doi: 10.1071/PP01200.
Carboxysomes, microcompartments that enhance the fixation of carbon dioxide by Rubisco, are found in several chemoautotrophs and in all cyanobacteria thus far examined. The genes for Rubisco large (cbbL) and small (cbbS) subunits (cbb for Calvin-Benson-Bassham), along with the genes (csoS) for the carboxysome shell peptides, are organized in a putative operon in Halothiobacillus neapolitanus in the following order: cbbL,cbbS, csoS2, csoS3, orfA, orfB, csoS1C, csoS1A, and csoS1B. DNA sequencing has revealed essentially the same operon in three other thiobacilli, Acidithiobacillus ferrooxidans, Thiomonas intermedia, and Thiobacillus denitrificans. The carboxysome genes are also clustered inSynechococcus sp. and Synechocystis sp., although in some cases certain genes lie outside the cluster. The genes, labelled ccm for CO2 concentrating mechanism, exist in Synechococcus PCC7942 in the order ccmK, ccmL, ccmM, ccmN, and ccmO, and are located upstream of the Rubisco genes. ccmO is absent, and multiple copies of ccmK exist in some species. The ccmK/ccmO and ccmL genes are homologues of csoS1CAB andorfAB, respectively. The ccmM and ccmN genes have no apparent counterpart in the thiobacilli. More recently, the genome sequence of four additional cyanobacteria has become available. The carboxysome genes in Nostoc punctiforme are clustered like, and are similar to, the genes of the earlier mentioned cyanobacteria. However, the three marine organisms Prochlorococcus marinus MIT9313, P. marinus MED4, and Synechococcus WH8102, possess an operon nearly identical to that found in thiobacilli. Furthermore, the genes exhibit surprising sequence identity to the carboxysome genes of the thiobacilli.
羧酶体是一种能增强核酮糖-1,5-二磷酸羧化酶（Rubisco）固定二氧化碳能力的微区室，存在于多种化能自养生物以及迄今为止检测过的所有蓝细菌中。核酮糖-1,5-二磷酸羧化酶大亚基（cbbL）和小亚基（cbbS）的基因（cbb代表卡尔文-本森-巴斯姆循环），连同羧酶体外壳肽的基因（csoS），在那不勒斯嗜盐硫杆菌中按以下顺序排列在一个假定的操纵子中：cbbL、cbbS、csoS2、csoS3、orfA、orfB、csoS1C、csoS1A和csoS1B。DNA测序显示，在另外三种硫杆菌，即氧化亚铁硫杆菌、中间硫单胞菌和脱氮硫杆菌中也存在基本相同的操纵子。羧酶体基因在聚球藻属和集胞藻属中也成簇存在，不过在某些情况下，某些基因位于该簇之外。这些标记为ccm（代表二氧化碳浓缩机制）的基因在聚球藻PCC7942中按ccmK、ccmL、ccmM、ccmN和ccmO的顺序存在，且位于核酮糖-1,5-二磷酸羧化酶基因的上游。ccmO不存在，并且在某些物种中存在多个ccmK拷贝。ccmK/ccmO和ccmL基因分别是csoS1CAB和orfAB的同源物。ccmM和ccmN基因在硫杆菌中没有明显的对应物。最近，又有另外四种蓝细菌的基因组序列公布。点状念珠藻中的羧酶体基因成簇排列，并且与上述蓝细菌的基因相似。然而，三种海洋生物，即海洋原绿球藻MIT9313、海洋原绿球藻MED4和聚球藻WH8102，拥有一个与硫杆菌中发现的操纵子几乎相同的操纵子。此外，这些基因与硫杆菌的羧酶体基因表现出惊人的序列同一性。
