6EE7

Small tetraheme cytochrome c from Shewanella oneidensis

6EE7 の概要

• エントリーDOI: 10.2210/pdb6ee7/pdb
• 分子名称: Periplasmic tetraheme cytochrome c CctA, HEME C, ZINC ION, ... (4 entities in total)
• 機能のキーワード: electron transfer, electron transport
• 由来する生物種: Shewanella oneidensis (strain MR-1)
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 12343.86

構造登録者

Huang, J.,Zarzycki, J.,Ducat, D.C.,Kramer, D.M. (登録日: 2018-08-13, 公開日: 2019-08-14, 最終更新日: 2024-11-20)

主引用文献

Huang, J.,Zarzycki, J.,Gunner, M.R.,Parson, W.W.,Kern, J.F.,Yano, J.,Ducat, D.C.,Kramer, D.M.
Mesoscopic to Macroscopic Electron Transfer by Hopping in a Crystal Network of Cytochromes.
J.Am.Chem.Soc., 142:10459-10467, 2020

PubMed Abstract: Rapid and directed electron transfer (ET) is essential for biological processes. While the rates of ET over 1-2 nm in proteins can largely be described by simplified nonadiabatic theory, it is not known how these processes scale to microscopic distances. We generated crystalline lattices of Small Tetraheme Cytochromes (STC) forming well-defined, three-dimensional networks of closely spaced redox centers that appear to be nearly ideal for multistep ET. Electrons were injected into specific locations in the STC crystals by direct photoreduction, and their redistribution was monitored by imaging. The results demonstrate ET over mesoscopic to microscopic (∼100 μm) distances through sequential hopping in a biologically based heme network. We estimate that a hypothetical "nanowire" composed of crystalline STC with a cross-section of about 100 cytochromes could support the anaerobic respiration of a cell. The crystalline lattice insulates mobile electrons from oxidation by O, as compared to those in cytochromes in solution, potentially allowing for efficient delivery of current without production of reactive oxygen species. The platform allows direct tests of whether the assumptions based on short-range ET hold for sequential ET over mesoscopic distances. We estimate that the interprotein ET across 6 Å between hemes in adjacent proteins was about 10 s, about 100-fold slower than expectations based on simplified theory. More detailed analyses implied that additional factors, possibly contributed by the crystal lattice, may strongly impact mesoscale ET mainly by increasing the reorganizational energy of interprotein ET, which suggests design strategies for engineering improved nanowires suitable for future bioelectronic materials.

PubMed: 32406683
DOI: 10.1021/jacs.0c02729

実験手法

X-RAY DIFFRACTION (1.394 Å)