影响类弹性蛋白多肽自组装成微球的因素及其作用机制

Factors and mechanism influencing elastin-like polypeptides self-assembled into micron-sized particles

摘要:

影响类弹性蛋白多肽 (ELPs) 自组装成微球的因素较多，目前尚缺乏系统研究。以类弹性蛋白多肽[KV8F]n为对象，利用动态光散射仪测定了不同条件下其自组装成微球的粒径。结果表明：随着分子量的增加ELPs形成的微球粒径也随之增大，粒径的均一度减小；当盐浓度低于0.4 mol/L时，盐浓度的增加，微球粒径相应增加，而盐浓度高于0.4 mol/L则呈减少的趋势，但粒径均大于1.1 μm；而当ELPs末端融合木聚糖酶和1,3-丙二醇氧化还原酶后，其自组装形成的微球粒径急剧减小，约为游离ELPs的1/10，分别为151.0 nm和 174.2 nm。导致这种现象的原因可能是酶分子和ELPs通过静电引力相互作用后，酶分子的空间位阻妨碍了ELPs分子的聚集。

Abstract:

Many factors influence the elastin-like polypeptides (ELPs) self-assembled into micron-sized particles. However, few efforts were made to investigate these factors. Using the ELPs [KV8F]n as the target, we studied systematically the factors with the dynamic light scattering. Our results show that the particle size increased and the uniform of particles decreased with the increase of the molecular weight. The analysis of size variation in self-assembled ELPs in response to changes in salt concentration indicated that the size increased with increasing the salt concentration, and the opposite response was observed when the concentration was above 0.4 mol/L. Under these conditions, the particles are micron-sized and larger than 1.1 μm. However, when the fusions containing the same ELPs and xylanase or 1,3-propanediol oxidoreductase, the size of the self-assembled ELPs particles decreased dramatically, which was only about 1/10 of that of the free ELPs. We proposed that the solvent accessible charged area of the enzymes could interact with the ELPs, the sterical hindrance of the enzymes prevent the aggregation of the ELPs. This might be the most important parameter in altering the particle size sharply.