Nishida Masayuki, Ida Noriko, Horio Mao, Takeuchi Toshifumi, Kamisuki Shinji, Murata Hiroshi, Kuramochi Kouji, Sugawara Fumio, Yoshida Hiromi, Mizushina Yoshiyuki
Laboratory of Food & Nutritional Sciences, Department of Nutritional Science, Kobe-Gakuin University, Nishi-ku, Kobe, Hyogo 651-2180, Japan.
Bioorg Med Chem. 2008 May 1;16(9):5115-22. doi: 10.1016/j.bmc.2008.03.021. Epub 2008 Mar 10.
Hymenoic acid (1) is a natural compound isolated from cultures of a fungus, Hymenochaetaceae sp., and this structure was determined by spectroscopic analyses. Compound 1 is a novel sesquiterpene, trans-4-[(1'E,5'S)-5'-carboxy-1'-methyl-1'-hexenyl]cyclohexanecarboxylic acid. This compound selectively inhibited the activity of human DNA polymerase lambda (pol lambda) in vitro, and 50% inhibition was observed at a concentration of 91.7microM. Compound 1 did not influence the activities of the other seven mammalian pols (i.e., pols alpha, gamma, delta, epsilon, eta, iota, and kappa), but also showed no effect even on the activity of pol beta, which is thought to have a very similar three-dimensional structure to the pol beta-like region of pol lambda. This compound also did not inhibit the activities of prokaryotic pols and other DNA metabolic enzymes tested. These results suggested that compound 1 could be a selective inhibitor of eukaryotic pol lambda. This compound had no inhibitory activities against two N-terminal truncated pol lambda, del-1 pol lambda (lacking nuclear localization signal (NLS), BRCA1 C-terminus (BRCT) domain [residues 133-575]), and del-2 pol lambda (lacking NLS, BRCT, domain and proline-rich region [residues 245-575]). The compound 1-induced inhibition of intact pol lambda activity was non-competitive with respect to both the DNA template-primer and the dNTP substrate. On the basis of these results, the pol lambda inhibitory mechanism of compound 1 is discussed.
膜酸（1）是从一种真菌（层孔菌科物种）培养物中分离出的天然化合物，其结构通过光谱分析确定。化合物1是一种新型倍半萜，反式-4-[(1'E,5'S)-5'-羧基-1'-甲基-1'-己烯基]环己烷羧酸。该化合物在体外选择性抑制人DNA聚合酶λ（pol λ）的活性，在浓度为91.7μM时观察到50%的抑制率。化合物1不影响其他七种哺乳动物聚合酶（即聚合酶α、γ、δ、ε、η、ι和κ）的活性，甚至对聚合酶β的活性也没有影响，聚合酶β被认为与聚合酶λ的聚合酶β样区域具有非常相似的三维结构。该化合物也不抑制所测试的原核聚合酶和其他DNA代谢酶的活性。这些结果表明化合物1可能是真核聚合酶λ的选择性抑制剂。该化合物对两种N端截短的聚合酶λ，即del-1聚合酶λ（缺乏核定位信号（NLS）、BRCA1 C端（BRCT）结构域[残基133 - 575]）和del-2聚合酶λ（缺乏NLS、BRCT结构域和富含脯氨酸区域[残基245 - 575]）没有抑制活性。化合物1诱导的对完整聚合酶λ活性的抑制对于DNA模板引物和dNTP底物均为非竞争性。基于这些结果，讨论了化合物1的聚合酶λ抑制机制。
