DNA BASE SEQUENCE EFFECTS IN CHEMICAL CARCINOGENESIS

描述：在此应用程序中要检验的主要假设是 定点修饰的构象和功能性质 具有单一立体化学定义的苯并[2]环氧化物的DNA序列 (BPDE)-脱氧鸟苷、BPDE-脱氧腺苷和脱氧腺苷加合物 派生自峡湾地区anti-benzo(c)phenathrene-3，4-diol-1，2-epoxide， 依赖于病变两侧的碱基。这一假设将通过以下方式检验 1)确定碱基序列对构象的影响 结构和立体化学定义的加合物的特征，2) 研究结构特征对 与这些病变的相互作用和切除，位于不同的位置 碱基序列上下文，通过体外核苷酸切除修复酶，以及 3)研究碱基序列对突变倾向的影响 DNA聚合酶对这些加合物的体外加工。一些DNA 通过核磁共振方法已经确定了加合物结构，因此 为理解结构生物活性提供了肥沃的基础 两性关系。这些具有结构特征的加合物将被选择 用于研究，紧随其后的是已知的富含鸟嘌呤序列的研究 BE在体内的突变热点，并通过系统的检查 病变两侧的两个碱基的影响。碱基序列的影响 关于外接诱导折弯和柔性铰链连接、弯曲方向和 螺旋解离，将使用凝胶电泳法进行检测。这个 首席调查者假设导致 灵活性可以影响加合物构象的多样性，可以是 由DNA中引物/模板连接处的多环残基假定 在体外复制酶复合体，从而影响诱变剂 加合物的特性。

DESCRIPTION: The major hypothesis to be tested in this application is that the conformational and functional properties of site-specifically modified DNA sequences with single, stereochemical defined benzopyrene diolepoxide (BPDE)-deoxyguanosine, BPDE-deoxyadenosine, and deoxyadenosine adducts derived from the fjord region anti-benzo(c)phenathrene-3,4-diol-1,2-epoxide, depend on the bases flanking the lesions. This hypothesis will be tested by 1) determining the effects of base sequence on the conformational characteristics of structurally and stereochemical defined adducts, 2) investigating the structural characteristics that are critical to the interactions with and excision of these lesions, positioned in different base sequence contexts, by nucleotide excision repair enzymes in vitro, and 3) investigating the effects of base sequence on the mutation prone processing of these adducts by DNA polymerases in vitro. A number of DNA adduct structures have already been established by NMR methods, thus providing a fertile basis for understanding structure biological activity relationships. These structurally characterized adducts will be selected for study, followed by studies of guanine-rich sequences that are known to be mutation hot spots in vivo, and by a systematic examination of the effects of the two bases flanking the lesions. The effects of base sequence on adduct induced bends and flexible hinge joints, direction of bending, and helix unwinding, will be examined using gel electrophoresis techniques. The principal investigator hypothesizes that base sequences leading to flexibility can affect the multiplicity of adduct conformations that can be assumed by the polycyclic residues at primer/template junctions in DNA replication enzyme complexes in vitro, thus influencing the mutagenic specificities of the adducts.