Black H S, Jirgensons B
Plant Physiol. 1967 May;42(5):731-5. doi: 10.1104/pp.42.5.731.
The interactions of aflatoxin B(1) with certain histone fractions and DNA were investigated by means of viscosity measurements and equilibrium dialysis. Two main histone fractions (F2b and F1), both lysine-rich, were examined after treatment with the toxin. Fraction 2b and 1 differ in amino acid composition and behave differently, in regard to gross conformation, in the presence of electrolytes. Aflatoxin increased the viscosity of fraction 2b but affected the viscosity of fraction 1 only slightly. Equilibrium dialysis experiments showed that aflatoxin was bound to both histone fractions. Aflatoxin also increased the viscosity of DNA and equilibrium dialysis showed that 1 molecule of the toxin was bound to approximately every 5 nucleotides of the nucleic acid. Binding constants for the aflatoxin complexes were calculated as 1000 for F2b, 700 for F1, and 5500 for DNA. The biological implications of these data, in regard to the effect aflatoxin has on the information-transcription process, are discussed.
通过粘度测量和平衡透析法研究了黄曲霉毒素B(1)与某些组蛋白组分及DNA的相互作用。在用毒素处理后,检测了两种主要的富含赖氨酸的组蛋白组分(F2b和F1)。组分2b和1在氨基酸组成上不同,并且在电解质存在下,就总体构象而言表现也不同。黄曲霉毒素增加了组分2b的粘度,但对组分1的粘度影响很小。平衡透析实验表明黄曲霉毒素与两种组蛋白组分均结合。黄曲霉毒素还增加了DNA的粘度,平衡透析表明每大约5个核酸核苷酸结合1个毒素分子。黄曲霉毒素复合物的结合常数计算得出F2b为1000,F1为700,DNA为5500。讨论了这些数据对于黄曲霉毒素对信息转录过程影响的生物学意义。