Trentmann S M, Saedler H, Gierl A
Max-Planck-Institut für Züchtungsforschung, Molekulare Pflanzengenetik, Köln, FRG.
Mol Gen Genet. 1993 Apr;238(1-2):201-8. doi: 10.1007/BF00279548.
The En/Spm-encoded TNPA protein binds to 12-bp DNA sequence motifs that are present in the subtermini of the transposable element. DNA binding of TNPA to monomeric and dimeric forms of the binding motif was analyzed by gel retardation and cross-linking studies. A DNA binding domain at the N-terminal and a dimerization domain at the C-terminal portion of TNPA were localized using deletion derivatives of TNPA. These domains are novel since no apparent homology has been found in the data bases. The stoichiometry of the TNPA-DNA complexes was analyzed. A special complex is formed with a tail-to-tail dimeric DNA binding motif, most probably involving two DNA-bound TNPA molecules that interact via their dimerization domains. In redox reactions the requirement for one or two disulfide bonds for DNA binding of TNPA was shown. The implications of these findings for the excision mechanism of En/Spm are discussed.
由En/Spm编码的TNPA蛋白与转座元件亚末端存在的12碱基对DNA序列基序结合。通过凝胶阻滞和交联研究分析了TNPA与结合基序单体和二聚体形式的DNA结合情况。使用TNPA的缺失衍生物定位了TNPA N端的DNA结合结构域和C端部分的二聚化结构域。这些结构域是新颖的，因为在数据库中未发现明显的同源性。分析了TNPA-DNA复合物的化学计量。一种特殊的复合物由尾对尾二聚体DNA结合基序形成，很可能涉及两个通过其二聚化结构域相互作用的与DNA结合的TNPA分子。在氧化还原反应中，显示了TNPA与DNA结合对一个或两个二硫键的需求。讨论了这些发现对En/Spm切除机制的影响。
