Tethered heme domains in a triheme cytochrome allow for increased electron transport distances.

Decades of research describe myriad redox enzymes that contain cofactors arranged in tightly packed chains facilitating rapid and controlled intra-protein electron transfer. Many such enzymes participate in extracellular electron transfer (EET), a process which allows microorganisms to conserve energy in anoxic environments by exploiting mineral oxides and other extracellular substrates as terminal electron acceptors. In this work, we describe the properties of the triheme cytochrome PgcA from Geobacter sulfurreducens.

A survey of the Desulfuromonadia "cytochromome" provides a glimpse of the unexplored diversity of multiheme cytochromes in nature.

Background: Multiheme cytochromes c (MHC) provide prokaryotes with a broad metabolic versatility that contributes to their role in the biogeochemical cycling of the elements and in energy production in bioelectrochemical systems. However, MHC have only been isolated and studied in detail from a limited number of species. Among these, Desulfuromonadia spp.

Genetic Code Expansion in MR-1 Allows Site-Specific Incorporation of Bioorthogonal Functional Groups into a -Type Cytochrome.

Genetic code expansion has enabled cellular synthesis of proteins containing unique chemical functional groups to allow the understanding and modulation of biological systems and engineer new biotechnology. Here, we report the development of efficient methods for site-specific incorporation of structurally diverse noncanonical amino acids (ncAAs) into proteins expressed in the electroactive bacterium MR-1. We demonstrate that the biosynthetic machinery for ncAA incorporation is compatible and orthogonal to the endogenous pathways of MR-1 for protein synthesis, maturation of -type cytochromes, and protein secretion.