Halazonetis T D, Kandil A N
Department of Cancer Research, Merck Sharp and Dohme Research Laboratories, West Point, PA 19486.
Science. 1992 Jan 24;255(5043):464-6. doi: 10.1126/science.1734524.
The c-Myc oncoprotein belongs to a family of proteins whose DNA binding domains contain a basic region-helix-loop-helix (bHLH) motif. Systematic mutagenesis of c-Myc revealed that dimerized bHLH motifs formed a parallel four-helix bundle with the amino termini of helices 1 and 2 directed toward the inner and outer nucleotides of the DNA binding site, respectively. Both the basic region and the carboxyl-terminal end of the loop contributed to DNA binding specificity. The DNA binding domain of c-Myc may therefore be structurally similar to that of restriction endonuclease Eco RI.
c-Myc癌蛋白属于一类蛋白质家族，其DNA结合结构域包含一个碱性区域-螺旋-环-螺旋（bHLH）基序。对c-Myc进行的系统诱变表明，二聚化的bHLH基序形成了一个平行的四螺旋束，其中螺旋1和螺旋2的氨基末端分别指向DNA结合位点的内侧和外侧核苷酸。碱性区域和环的羧基末端都对DNA结合特异性有贡献。因此，c-Myc的DNA结合结构域在结构上可能与限制性内切酶Eco RI的相似。
