Menkens A E, Cashmore A R
Department of Biology, University of Pennsylvania, Philadelphia 19104-6018.
Proc Natl Acad Sci U S A. 1994 Mar 29;91(7):2522-6. doi: 10.1073/pnas.91.7.2522.
A fourth member of the Arabidopsis G-box-binding factor (GBF) family of bZIP proteins, GBF4, has been isolated and characterized. In a manner reminiscent of the Fos-related oncoproteins of mammalian systems, GBF4 cannot bind to DNA as a homodimer, although it contains a basic region capable of specifically recognizing the G-box and G-box-like elements. However, GBF4 can interact with GBF2 and GBF3 to bind DNA as heterodimers. Mutagenesis of the leucine zipper of GBF4 indicates that the mutation of a single amino acid confers upon the protein the ability to recognize the G-box as a homodimer, apparently by altering the charge distribution within the leucine zipper.
拟南芥bZIP蛋白家族中G-box结合因子（GBF）的第四个成员GBF4已被分离和鉴定。与哺乳动物系统中Fos相关的癌蛋白类似，GBF4不能作为同二聚体结合DNA，尽管它含有一个能够特异性识别G-box和G-box样元件的碱性区域。然而，GBF4可以与GBF2和GBF3相互作用，以异二聚体形式结合DNA。GBF4亮氨酸拉链的诱变表明，单个氨基酸的突变赋予该蛋白作为同二聚体识别G-box的能力，这显然是通过改变亮氨酸拉链内的电荷分布实现的。
