Konishi T, Shinohara K, Yamada K, Sasaki Y
Department of Food Science and Technology, Faculty of Agriculture, Kyoto University, Japan.
Plant Cell Physiol. 1996 Mar;37(2):117-22. doi: 10.1093/oxfordjournals.pcp.a028920.
The presence and the absence of a prokaryote type and a eukaryote type of acetyl-CoA carboxylase (EC 6.4.1.2; ACCase) were examined in members of 28 plant families by two distinct methods: the detection of biotinylated subunits of ACCase with a streptavidin probe, and the detection of the accD gene, which encodes a subunit of the prokaryotic ACCase, by Southern hybridization analysis. The protein extracts of all the plants studied contained a biotinylated polypeptide of 220 kDa, which was probably the eukaryotic ACCase. All the plants but those belonging to Gramineae also contained a biotinylated polypeptide of ca. 35 kDa, which is a putative subunit of the prokaryotic ACCase. In all plants but those in Gramineae, the ca. 35 kDa polypeptide was found in the protein extracts of plastids, while the 220 kDa polypeptide was absent from these plastid extracts. The plastid extracts of the plants in Gramineae contained the 220 kDa polypeptide, as did the homogenates of the leaves. Southern hybridization analysis demonstrated that all the plants but those in the Gramineae contained the accD gene. These findings suggest that most higher plants have the prokaryotic ACCase in the plastids and the eukaryotic ACCase in the cytosol. Only Gramineae plants might contain the eukaryotic ACCases both in the plastids and in the cytosol. The origin of the plastid-located eukaryotic ACCase in Gramineae is discussed as the first possible example of substitution of a plastid gene by a nuclear gene for a non-ribosomal component.
采用两种不同方法，对28个植物科的植物成员中是否存在原核生物型和真核生物型乙酰辅酶A羧化酶（EC 6.4.1.2；ACCase）进行了检测：一种是用链霉亲和素探针检测ACCase的生物素化亚基，另一种是通过Southern杂交分析检测编码原核生物ACCase一个亚基的accD基因。所有研究植物的蛋白质提取物中都含有一条220 kDa的生物素化多肽，它可能是真核生物ACCase。除禾本科植物外，所有植物还含有一条约35 kDa的生物素化多肽，它是原核生物ACCase的一个假定亚基。除禾本科植物外，在所有植物中，约35 kDa的多肽存在于质体的蛋白质提取物中，而220 kDa的多肽在这些质体提取物中不存在。禾本科植物的质体提取物中含有220 kDa的多肽，叶片匀浆中也含有。Southern杂交分析表明，除禾本科植物外，所有植物都含有accD基因。这些发现表明，大多数高等植物在质体中具有原核生物ACCase，在细胞质中具有真核生物ACCase。只有禾本科植物可能在质体和细胞质中都含有真核生物ACCase。讨论了禾本科植物中质体定位的真核生物ACCase的起源，这可能是一个非核糖体成分的质体基因被核基因取代的首个例子。
