Instituto de Investigaciones Biológicas IIB-CONICET-UNMdP, Funes 3250 3er nivel 7600 Mar del Plata, Argentina.
Plant Sci. 2012 May;187:97-104. doi: 10.1016/j.plantsci.2012.02.001. Epub 2012 Feb 10.
Many photosynthetic organisms have developed inorganic carbon (Ci) concentrating mechanisms (CCMs) that increase the CO₂ concentration within the vicinity of ribulose-1,5-bisphosphate carboxylase/oxygenase (RubisCO). Several CCMs, such as four carbon (C4) and crassulacean acid metabolism (CAM), bicarbonate accumulation systems and capsular structures around RubisCO have been described in great detail. These systems are believed to have evolved several times as mechanisms that acclimate organisms to unfavourable growth conditions. Based on recent experimental evidence we propose the occurrence of another more general CCM system present in all plants. This basal CCM (bCCM) is supposed to be composed of mitochondrial carbonic anhydrases (a β-type carbonic anhydrase and the γ-type carbonic anhydrase domain of the mitochondrial NADH dehydrogenase complex) and probably further unknown components. The bCCM is proposed to reduce leakage of CO₂ from plant cells and allow efficient recycling of mitochondrial CO₂ for carbon fixation in chloroplasts.
许多光合作用生物已经进化出无机碳（Ci）浓缩机制（CCMs），从而增加了核酮糖-1,5-二磷酸羧化酶/加氧酶（RubisCO）附近的 CO₂浓度。已经详细描述了几种 CCM，如四碳（C4）和景天酸代谢（CAM）、碳酸氢盐积累系统以及 RubisCO 周围的囊状结构。这些系统被认为是生物体适应不利生长条件的机制，已经进化了多次。基于最近的实验证据，我们提出了另一种存在于所有植物中的更普遍的 CCM 系统。这个基础 CCM（bCCM）被认为由线粒体碳酸酐酶（一种β型碳酸酐酶和线粒体 NADH 脱氢酶复合物的γ型碳酸酐酶结构域）和可能进一步未知的成分组成。bCCM 被提议减少 CO₂从植物细胞中的泄漏，并允许线粒体 CO₂的有效回收，用于叶绿体中的碳固定。
