Carroll R B, Neet K E, Goldthwait D A
Proc Natl Acad Sci U S A. 1972 Sep;69(9):2741-4. doi: 10.1073/pnas.69.9.2741.
The self-association of gene-32 protein has been studied by sedimentation equilibrium centrifugation and polyacrylamide gel electrophoresis, in order to better understand its role in DNA replication and genetic recombination. The monomer molecular weight of gene-32 protein is 38,000 in guanidine hydrochloride and 34,000 in sodium dodecyl sulfate, in agreement with the results of Alberts and coworkers. Stable dimers of gene-32 protein occur under various conditions, among which are high ionic strength and pH 10. The occurrence of stable dimers under some conditions and higher aggregates under others indicates there are two types of protein-protein interactions occurring in gene-32 protein self-association. The association that occurs above about 0.1 mg/ml concentration of protein produces at least decamers.A model for the DNA replication fork is postulated that requires the two different interactions that occur in gene-32 protein aggregation. In the model, gene-32 protein holds the two strands of the DNA duplex in a conformation that prevents their reannealing and, therefore, facilitates replication and recombination.
为了更好地理解基因32蛋白在DNA复制和基因重组中的作用，通过沉降平衡离心和聚丙烯酰胺凝胶电泳对其自身缔合进行了研究。基因32蛋白在盐酸胍中的单体分子量为38,000，在十二烷基硫酸钠中的单体分子量为34,000，这与阿尔伯茨及其同事的结果一致。基因32蛋白的稳定二聚体在各种条件下都会出现，其中包括高离子强度和pH值为10的条件。在某些条件下出现稳定二聚体，而在其他条件下出现更高聚集体，这表明基因32蛋白自身缔合过程中存在两种类型的蛋白质-蛋白质相互作用。蛋白质浓度高于约0.1 mg/ml时发生的缔合至少会产生十聚体。假定了一个DNA复制叉模型，该模型需要基因32蛋白聚集中发生的两种不同相互作用。在该模型中，基因32蛋白使DNA双链保持一种构象，防止它们重新退火，因此促进复制和重组。
