Kim Yun Jae, Cha Sun-Shin, Lee Hyun Sook, Ryu Yong Gu, Bae Seung Seob, Cho Yona, Cho Hyun-Soo, Kim Sang-Jin, Kwon Suk-Tae, Lee Jung-Hyun, Kang Sung Gyun
Korea Ocean Research and Development Institute, Ansan P.O. Box 29, Seoul 425-600, Korea.
J Microbiol Biotechnol. 2008 Aug;18(8):1377-85.
The uracil-sensing domain in archaeal family B-type DNA polymerases recognizes pro-mutagenic uracils in the DNA template, leading to stalling of DNA polymerases. Here, we describe our new findings regarding the molecular mechanism underpinning the stalling of polymerases. We observed that two successive deaminated bases were required to stall TNA1 and KOD1 DNA polymerases, whereas a single deaminated base was enough for stalling Pfu DNA polymerase, in spite of the virtually identical uracil-sensing domains. TNA1 and KOD1 DNA polymerases have a much higher extension rate than Pfu DNA polymerase; decreasing the extension rate resulted in stalling by TNA1 and KOD1 DNA polymerases at a single deaminated base. These results strongly suggest that these polymerases require two factors to stop DNA polymerization at a single deaminated base: the presence of the uracil-sensing domain and a relatively slow extension rate.
古菌B族DNA聚合酶中的尿嘧啶传感结构域可识别DNA模板中具有诱变作用的尿嘧啶，导致DNA聚合酶停滞。在此，我们描述了关于聚合酶停滞背后分子机制的新发现。我们观察到，使TNA1和KOD1 DNA聚合酶停滞需要两个连续的脱氨基碱基，而尽管尿嘧啶传感结构域几乎相同，但单个脱氨基碱基就足以使Pfu DNA聚合酶停滞。TNA1和KOD1 DNA聚合酶的延伸速率比Pfu DNA聚合酶高得多；降低延伸速率会导致TNA1和KOD1 DNA聚合酶在单个脱氨基碱基处停滞。这些结果有力地表明，这些聚合酶在单个脱氨基碱基处停止DNA聚合需要两个因素：尿嘧啶传感结构域的存在和相对较慢的延伸速率。
