The robustness of porin-cytochrome gene clusters from Geobacter metallireducens in extracellular electron transfer.

Abstract

The Gram-negative bacterium Geobacter metallireducens is of environmental and biotechnological significance. Crucial to the unique physiology of G. metallireducens is its extracellular electron transfer (EET) capability. This investigation sheds new light on the robust roles of the three porin-cytochrome (pcc) gene clusters, which are directly involved in EET across the bacterial outer membrane, in the EET of G. metallireducens. In addition to their essential roles, these gene clusters also play distinct, overlapping, and compensatory roles in the EET of G. metallireducens. The distinct roles of the pcc gene clusters enable G. metallireducens to mediate EET to a diverse group of electron acceptors for anaerobic respirations. The overlapping and compensatory roles of the pcc gene clusters enable G. metallireducens to maintain and restore its EET capability for anaerobic growth when one or two of its three pcc gene clusters are deleted from the genome.