7O7G

Crystal structure of the Shewanella oneidensis MR1 MtrC mutant H561M

Summary for 7O7G

• Entry DOI: 10.2210/pdb7o7g/pdb
• Related: 4LM8
• Descriptor: Extracellular iron oxide respiratory system surface decaheme cytochrome c component MtrC, HEME C, CALCIUM ION, ... (6 entities in total)
• Functional Keywords: electron transfer activity oxidoreductase activity ion binding cation binding metal ion binding, electron transport
• Biological source: Shewanella oneidensis (strain MR-1)
• Total number of polymer chains: 1
• Total formula weight: 78445.53

Authors

Edwards, M.J.,van Wonderen, J.H.,Newton-Payne, S.E.,Butt, J.N.,Clarke, T.A. (deposition date: 2021-04-13, release date: 2021-10-06, Last modification date: 2024-11-13)

Primary citation

van Wonderen, J.H.,Adamczyk, K.,Wu, X.,Jiang, X.,Piper, S.E.H.,Hall, C.R.,Edwards, M.J.,Clarke, T.A.,Zhang, H.,Jeuken, L.J.C.,Sazanovich, I.V.,Towrie, M.,Blumberger, J.,Meech, S.R.,Butt, J.N.
Nanosecond heme-to-heme electron transfer rates in a multiheme cytochrome nanowire reported by a spectrally unique His/Met-ligated heme.
Proc.Natl.Acad.Sci.USA, 118:-, 2021

PubMed Abstract: Proteins achieve efficient energy storage and conversion through electron transfer along a series of redox cofactors. Multiheme cytochromes are notable examples. These proteins transfer electrons over distance scales of several nanometers to >10 μm and in so doing they couple cellular metabolism with extracellular redox partners including electrodes. Here, we report pump-probe spectroscopy that provides a direct measure of the intrinsic rates of heme-heme electron transfer in this fascinating class of proteins. Our study took advantage of a spectrally unique His/Met-ligated heme introduced at a defined site within the decaheme extracellular MtrC protein of We observed rates of heme-to-heme electron transfer on the order of 10 s (3.7 to 4.3 Å edge-to-edge distance), in good agreement with predictions based on density functional and molecular dynamics calculations. These rates are among the highest reported for ground-state electron transfer in biology. Yet, some fall 2 to 3 orders of magnitude below the Moser-Dutton ruler because electron transfer at these short distances is through space and therefore associated with a higher tunneling barrier than the through-protein tunneling scenario that is usual at longer distances. Moreover, we show that the His/Met-ligated heme creates an electron sink that stabilizes the charge separated state on the 100-μs time scale. This feature could be exploited in future designs of multiheme cytochromes as components of versatile photosynthetic biohybrid assemblies.

PubMed: 34556577
DOI: 10.1073/pnas.2107939118

Experimental method

X-RAY DIFFRACTION (1.6 Å)