Controlling the reduction midpoint potential of heme B is a key factor in many bioelectrochemical reactions, including long-range electron transport. Currently, there are a number of globular model protein systems to study this biophysical parameter; however, there are none for large polymeric protein model systems (e.g., the OmcS protein from ). Peptide amphiphiles, short peptides with a lipid tail that polymerize into fibrous structures, fill this gap. Here, we show a peptide amphiphile model system where one can tune the electrochemical potential of heme B by changing the loading ratio and peptide sequence. Changing the loading ratio resulted in the most significant increase, with values as high as −22 mV down to −224 mV. Circular dichroism spectra of certain sequences show Cotton effects at lower loading ratios that disappear as more heme B is added, indicating an ordered environment that becomes disrupted if heme B is overpacked. These findings can contribute to the design of functional self-assembling biomaterials.

中文翻译：

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通过序列和血红素负载比控制肽两亲纤维中的血红素氧化还原特性


控制血红素 B 的还原中点电位是许多生物电化学反应（包括长程电子传输）的关键因素。目前，有多种球状模型蛋白质系统来研究这一生物物理参数；然而，没有大型聚合蛋白质模型系统（例如来自 的 OmcS 蛋白质）。肽两亲物，即带有脂质尾部的短肽，可聚合成纤维结构，填补了这一空白。在这里，我们展示了一种肽两亲物模型系统，可以通过改变负载比和肽序列来调节血红素 B 的电化学势。改变负载比导致最显着的增加，值高达 -22 mV 低至 -224 mV。某些序列的圆二色光谱显示较低负载率下的棉花效应随着添加更多血红素 B 而消失，表明如果血红素 B 过度堆积，有序环境就会被破坏。这些发现有助于功能性自组装生物材料的设计。