Sala F, Amileni A R, Parisi B, Spadari S
Eur J Biochem. 1980 Nov;112(2):211-7. doi: 10.1111/j.1432-1033.1980.tb07196.x.
A DNA polymerase has been extracted from spinach chloroplasts and purified by chromatography on DEAE-cellulose and hydroxyapatite. A great similarity between the purified chloroplast polymerase and the mammalian mitochondrial DNA polymerase gamma was found by several criteria: preference for the synthetic primer-template (dT)12-18 . poly(rA), optimal requirement for Mn2+ (0.1-1.0 mM), KCl (100 mM) and pH (8-9), high relative molecular mass (approximately 105,000), resistance to aphidicolin and inhibition by N-ethylmaleimide. Some peculiar features of the chloroplast DNA polymerase have, however, been noticed. The mammalian DNA polymerase gamma has been suggested to be responsible for the replication of mitochondrial DNA. Thus, both the presence of a gamma-like DNA polymerase in chloroplasts and the similarities between the chloroplast and the mitochondrial DNA (absence of a nucleosomal structure an presence of displacement loops) lead to the suggestion that chloroplast DNA is also replicated by a gamma-like DNA polymerase and that the gamma polymerases present in eukaryotes are, therefore, involved in a strand-displacement DNA synthesis. An alpha-like DNA polymerase activity, present and predominant in crude leaf extracts, was practically absent from purified chloroplast preparations.
已从菠菜叶绿体中提取出一种DNA聚合酶，并通过在DEAE - 纤维素和羟基磷灰石上进行层析纯化。通过几个标准发现纯化的叶绿体聚合酶与哺乳动物线粒体DNA聚合酶γ有很大相似性：对合成引物 - 模板（dT）12 - 18·聚（rA）的偏好，对Mn2 +（0.1 - 1.0 mM）、KCl（100 mM）和pH（8 - 9）的最佳需求，高相对分子质量（约105,000），对阿非科林的抗性以及被N - 乙基马来酰亚胺抑制。然而，已注意到叶绿体DNA聚合酶的一些独特特征。哺乳动物DNA聚合酶γ被认为负责线粒体DNA的复制。因此，叶绿体中存在类似γ的DNA聚合酶以及叶绿体和线粒体DNA之间的相似性（不存在核小体结构和存在置换环）表明叶绿体DNA也由类似γ的DNA聚合酶复制，因此真核生物中存在的γ聚合酶参与链置换DNA合成。在粗叶提取物中存在且占主导的α样DNA聚合酶活性在纯化的叶绿体制剂中几乎不存在。
