Cui Zixian, Brna Elliot A, Crawford Matthew A, Treerat Puthayalai, Alimadad Mobina, Hughes Molly A, Letteri Rachel A
Department of Chemical Engineering, University of Virginia, Charlottesville, Virginia 22903, United States.
Division of Infectious Diseases & International Health, Department of Medicine, University of Virginia, Charlottesville, Virginia 22908, United States.
Macromolecules. 2025 Feb 5;58(4):2073-2084. doi: 10.1021/acs.macromol.4c02762. eCollection 2025 Feb 25.
Conjugating antimicrobial peptides (AMPs) to nonlinear polymers is a promising strategy to overcome the translational challenges of AMPs toward treating infections caused by antibiotic-resistant bacteria. Nonlinear polymers, and therefore conjugates, can be prepared with various architectures (e.g., star-shaped, comb-like, hyperbranched, etc.), however, the effects of polymer architecture on antimicrobial performance and related properties, like size and morphology in solution and secondary structure, are not yet well-understood. Here, we compare conjugates of the human chemokine-derived AMP stapled P9 with poly(ethylene glycol) (PEG) prepared in two of the major nonlinear architectures: star-shaped and comb-like. At comparable molecular weights and compositions (peptide wt %), comb-like conjugates afford increased helicity, solubility, antimicrobial activity, and proteolytic stability compared to star-shaped analogs. We then leveraged the expansive design space of comb-like architectures to prepare conjugates with different backbone lengths and PEG side chain lengths, with shorter PEG side chains leading to increased helicity, yet potentially less shielding from proteolytic degradation and the longest backbone lengths furnishing the most potent antimicrobial activity. Both comb-like and star-shaped conjugates display high zeta potential, indicating that the cationic AMPs were accessible for electrostatic interactions with bacterial membranes. Yet, the comb-like conjugates showed a higher fraction of unimolecular structures indicative of a lower propensity for supramolecular assembly that could be encumbering the desired AMP-bacteria interactions in the star-shaped conjugates. Together, our work shows comb-like AMP-polymer conjugates to outperform analogous star-shaped conjugates, while adding design flexibility to access an expansive range of monomer chemistries, monomer distributions, and backbone lengths to modulate performance-determining properties and ultimately furnish an effective suite of AMP-polymer materials as alternatives to conventional antibiotics for combatting bacterial infections.
将抗菌肽（AMPs）与非线性聚合物偶联是一种很有前景的策略，可克服AMPs在治疗由耐抗生素细菌引起的感染方面的转化挑战。非线性聚合物以及由此形成的偶联物可以制备成各种结构（例如，星形、梳状、超支化等），然而，聚合物结构对抗菌性能和相关性质（如溶液中的尺寸和形态以及二级结构）的影响尚未得到充分理解。在这里，我们比较了人类趋化因子衍生的AMPs——订书钉状P9与聚乙二醇（PEG）在两种主要非线性结构（星形和梳状）中制备的偶联物。在分子量和组成（肽重量百分比）相当的情况下，与星形类似物相比，梳状偶联物具有更高的螺旋度、溶解度、抗菌活性和蛋白水解稳定性。然后，我们利用梳状结构广阔的设计空间制备了具有不同主链长度和PEG侧链长度的偶联物，较短的PEG侧链导致螺旋度增加，但可能对蛋白水解降解的屏蔽作用较小，而最长的主链长度则提供了最强的抗菌活性。梳状和星形偶联物都显示出高ζ电位，表明阳离子AMPs可用于与细菌膜进行静电相互作用。然而，梳状偶联物显示出更高比例的单分子结构，这表明其超分子组装倾向较低，而超分子组装可能会阻碍星形偶联物中所需的AMPs与细菌的相互作用。总之，我们的工作表明梳状AMPs - 聚合物偶联物优于类似的星形偶联物，同时增加了设计灵活性，以获得广泛的单体化学、单体分布和主链长度，从而调节性能决定性质，并最终提供一套有效的AMPs - 聚合物材料，作为对抗细菌感染的传统抗生素的替代品。
