Rothman R H
J Bacteriol. 1980 Jul;143(1):520-4. doi: 10.1128/jb.143.1.520-524.1980.
The observation that polA1 and recL152 mutations result in both slow pyrimidine dimer excision and large repair patch size leads to the hypothesis that patch size is directly related to the rate of excision. In this study caffeine, a known inhibitor of excision repair, was used to examine the extent of correlation between excision rate and patch size by measuring patch size in the presence of several concentrations of caffeine. Both the rate of excision and the resistance to ultraviolet radiation were reduced with increasing concentrations of caffeine after irradiation. Caffeine also inhibited the rate at which incisions were made and prolonged the time required to rejoin the discontinuities. Patch size, however, was unaffected by caffeine treatment.
polA1和recL152突变导致嘧啶二聚体切除缓慢且修复补丁尺寸较大，这一观察结果引出了补丁尺寸与切除速率直接相关的假说。在本研究中，咖啡因是一种已知的切除修复抑制剂，通过测量几种咖啡因浓度下的补丁尺寸，来检验切除速率与补丁尺寸之间的相关程度。照射后，随着咖啡因浓度的增加，切除速率和对紫外线辐射的抗性均降低。咖啡因还抑制了切口形成的速率，并延长了重新连接间断所需的时间。然而，补丁尺寸不受咖啡因处理的影响。
