Nayvelt Irina, Thomas Thresia, Thomas T J
Department of Medicine, Robert Wood Johnson Medical School, University of Medicine and Dentistry of New Jersey, New Brunswick, New Jersey 08903, USA.
Biomacromolecules. 2007 Feb;8(2):477-84. doi: 10.1021/bm0605863.
We studied the effectiveness of trilysine (Lys3), tetralysine (Lys4), pentalysine (Lys5), and poly-l-lysine (PLL) (MW 50000) on lambda-DNA nanoparticle formation and characterized the size, shape, and stability of nanoparticles. Light scattering experiments showed EC50 (lysine concentration at 50% DNA compaction) values of approximately 0.0036, 2, and 20 micromol/L, respectively, for PLL, Lys5, and Lys4 at 10 mM [Na+]. Plots of log EC50 versus log [Na+] showed positive slopes of 1.09 and 1.7, respectively, for Lys4 and Lys5 and a negative slope of -0.1 for PLL. Hydrodynamic radii of oligolysine condensed particles increased (48-173 nm) with increasing [Na+], whereas no significant change occurred to nanoparticles formed with PLL. There was an increase in the size of nanoparticles formed with Lys5 at >40 degrees C, whereas no such change occurred with PLL. The DNA melting temperature increased with oligolysine concentration. These results indicate distinct differences in the mechanism(s) by which oligolysines and PLL provoke DNA condensation to nanoparticles.
我们研究了三赖氨酸（Lys3）、四赖氨酸（Lys4）、五赖氨酸（Lys5）和聚-L-赖氨酸（PLL）（分子量50000）对λ-DNA纳米颗粒形成的有效性，并对纳米颗粒的大小、形状和稳定性进行了表征。光散射实验表明，在10 mM [Na+]条件下，PLL、Lys5和Lys4的EC50（50%DNA压缩时的赖氨酸浓度）值分别约为0.0036、2和20 μmol/L。log EC50对log [Na+]的曲线显示，Lys4和Lys5的正斜率分别为1.09和1.7，而PLL的负斜率为-0.1。随着[Na+]的增加，寡聚赖氨酸凝聚颗粒的流体动力学半径增大（48 - 173 nm），而用PLL形成的纳米颗粒没有显著变化。在>40℃时，用Lys5形成的纳米颗粒尺寸增加，而PLL形成的纳米颗粒没有这种变化。DNA解链温度随寡聚赖氨酸浓度的增加而升高。这些结果表明，寡聚赖氨酸和PLL促使DNA凝聚成纳米颗粒的机制存在明显差异。
