Bulk Biopolyelectrolyte Complexes from Homopolypeptides: Solid “Salt Bridges”
Bulk Biopolyelectrolyte Complexes from Homopolypeptides: Solid “Salt Bridges”
复制标题
来自同聚肽的本体生物聚电解质复合物：固体“盐桥”
DOI：
10.1021/acs.biomac.2c01456
复制
发表时间：
2023
影响因子：
6.2
通讯作者：
Schlenoff, Joseph B.
中科院分区：
文献类型：
--
作者：
Digby, Zachary A.;Chen, Yuhui;Akkaoui, Khalil;Schlenoff, Joseph B.
盐桥，带相反电荷的氨基酸之间的配对，分散在整个蛋白质中，以帮助折叠和相互作用。生物聚电解质复合物（BioPEC）之间的同聚肽聚-l-精氨酸（PLR）和聚-l-赖氨酸（PLK）与三磷酸钠（STPP），以及从多肽的组合。对这些高盐桥密度材料的粘弹性测量表明，许多材料本质上是固体，甚至是玻璃状的。尽管多肽-磷酸盐复合物在室温下具有相似的模量，但PLR-STPP复合物显示出PLK-STPP中未观察到的高于70 °C的不寻常的熔融事件。差示扫描量热法证实了这一结果。红外光谱分析表明PLK-STPP体系含有β折叠，而PLR-STPP体系不含β折叠。制备PLR和PLK与聚-l-天冬氨酸（PLD）和聚-l-谷氨酸（PLE）的化学计量的宏观BioPEC。发现PLR-PLD经历类似于PLR-STPP中的解链事件。ATR-FTIR研究表明，用PLD制备的BioPEC不含β-折叠，而由PLE组成的BioPEC含有β-折叠。这项工作说明了这些生物材料的独特性质的扩展调色板，例如含有PLE和PLD的佩奇之间的强粘弹性差异，即使它们在侧链上仅相差一个碳。
Salt bridges, pairings between oppositely charged amino acids, are dispersed throughout proteins to assist folding and interactions. Biopolyelectrolyte complexes (BioPECs) were made between the homopolypeptides poly-l-arginine (PLR) and poly-l-lysine (PLK) with sodium triphosphate (STPP), as well as from polypeptide-only combinations. Viscoelastic measurements on these high salt bridge density materials showed many were solid, even glassy, in nature. Although the polypeptide–phosphate complexes had similar moduli at room temperature, the PLR–STPP complex displayed an unusual melting event above 70 °C not seen in PLK–STPP. This event was supported with differential scanning calorimetry. Infrared spectroscopy showed the PLK–STPP system contained β-sheets, while PLR–STPP did not. Stoichiometric, macroscopic BioPECs of PLR and PLK with poly-l-aspartic acid (PLD) and poly-l-glutamic acid (PLE) were made. PLR–PLD was found to undergo a melting event similar to that in PLR–STPP. ATR-FTIR studies showed that BioPECs made with PLD do not contain β-sheets, while those composed of PLE do. This work illustrates an expanded palette of unique properties from these biomaterials, such as strong viscoelastic differences between PECs containing PLE and PLD, even though they differ by only one carbon on the side chain.