PDF(Pubmed)
Abstract：
Geobacter sulfurreducens profoundly shapes Earth\'s biogeochemistry by discharging respiratory electrons to minerals and other microbes through filaments of a two-decades-long debated identity. Cryogenic electron microscopy has revealed filaments of redox-active cytochromes, but the same filaments have exhibited hallmarks of organic metal-like conductivity under cytochrome denaturing/inhibiting conditions. Prior structure-based calculations and kinetic analyses on multi-heme proteins are synthesized herein to propose that a minimum of ~7 cytochrome \'nanowires\' can carry the respiratory flux of a Geobacter cell, which is known to express somewhat more (≥20) filaments to increase the likelihood of productive contacts. By contrast, prior electrical and spectroscopic structural characterizations are argued to be physiologically irrelevant or physically implausible for the known cytochrome filaments because of experimental artifacts and sample impurities. This perspective clarifies our mechanistic understanding of physiological metal-microbe interactions and advances synthetic biology efforts to optimize those interactions for bioremediation and energy or chemical production.
摘要：
通过将呼吸电子通过长达20年之久的争议身份的细丝释放到矿物质和其他微生物，从而还原了地球的生物地球化学。低温电子显微镜显示了氧化还原活性细胞色素的细丝，但是相同的细丝在细胞色素变性/抑制条件下表现出有机金属样导电性的标志。本文合成了对多血红素蛋白的基于结构的先前计算和动力学分析，以提出至少约7个细胞色素纳米线可以携带Geobacter细胞的呼吸通量，已知表达更多（≥20）细丝以增加生产性接触的可能性。相比之下,由于实验伪影和样品杂质，先前的电学和光谱结构表征被认为与已知的细胞色素丝在生理上无关或在物理上不合理。这种观点澄清了我们对生理金属-微生物相互作用的机械理解，并推进了合成生物学努力，以优化生物修复和能源或化学生产的相互作用。
