Reha-Krantz L J
Department of Biological Sciences, University of Alberta, Edmonton, Canada.
Trends Biochem Sci. 1995 Apr;20(4):136-40. doi: 10.1016/s0968-0004(00)88987-2.
Mutant bacteriophage T4 DNA polymerases exist that appear primarily to reduce the frequency of AT-to-GC transitions when this [antimutator' phenotype is assessed by genetic methods. This observation disagrees with in vitro studies, which indicate that T4 antimutator DNA polymerases have increased proofreading abilities and effectively edit all types of base substitution errors. One explanation that reconciles the apparent in vivo mutational specificity of antimutator DNA polymerases with their biochemical properties is that the in vivo mutational specificity identifies mismatched primer-termini that are corrected less efficiently by the wild-type level of proofreading activity, but are corrected if proofreading is increased.
存在一些突变型噬菌体T4 DNA聚合酶，当通过遗传学方法评估这种“抗突变”表型时，这些酶主要表现为降低AT到GC转换的频率。这一观察结果与体外研究结果不一致，体外研究表明T4抗突变DNA聚合酶具有增强的校对能力，能有效编辑所有类型的碱基替代错误。一种能使抗突变DNA聚合酶在体内明显的突变特异性与其生化特性相协调的解释是，体内突变特异性识别的错配引物末端，在野生型校对活性水平下校正效率较低，但在校对能力增强时则可被校正。
