Worah D M, Gibboney K M, Yang L M, York S S
Biochemistry. 1978 Oct 17;17(21):4487-92. doi: 10.1021/bi00614a020.
The association of lac repressor with poly[d(A-T)] was monitored with the fluorescent prob 8-anilino-1-naphthalenesulfonate (Ans). Excess poly[d(A-T)] decreased the emission intensity of the repressor--Ans complex by 30%. Fluorescence titrations indicated that 33 +/- 4 base pairs were required to bind all of the repressor. Sedimentation studies indicated, however, that all of the repressor sedimented as a protein--DNA complex with as few as 10 to 15 base pairs per tetramer, even in the presence of Ans. These data are interpreted with two models: one where repressors bind to both sides of the DNA (Butler, A. P., et al. (1977) Biochemistry 16, 4757: Zingsheim, H.P., et al. (1977) J. Mol. Biol. 115, 565), the other where a double layer of repressors bind to a single side of the DNA. Removal of the amino-terminal regions from the repressor decreased the fluorescence from bound Ans by 77%. The amino-terminal fragments alone did not enhance Ans fluorescence.
利用荧光探针8-苯胺基-1-萘磺酸盐（Ans）监测乳糖阻遏物与聚[d（A-T）]的结合情况。过量的聚[d（A-T）]使阻遏物 - Ans复合物的发射强度降低了30%。荧光滴定表明，结合所有阻遏物需要33±4个碱基对。然而，沉降研究表明，即使在存在Ans的情况下，所有阻遏物都以蛋白质 - DNA复合物的形式沉降，每个四聚体仅有10至15个碱基对。这些数据用两种模型来解释：一种是阻遏物与DNA的两侧结合（巴特勒，A.P.等人（1977年）《生物化学》16卷，475页；津斯海姆，H.P.等人（1977年）《分子生物学杂志》115卷，565页），另一种是双层阻遏物与DNA的一侧结合。从阻遏物上去除氨基末端区域使结合的Ans的荧光降低了77%。单独的氨基末端片段不会增强Ans荧光。
