PMID: 30030519

Authors:

Zong S, Wu M, Gu J, Liu T, Guo R, Yang M

Title:

Structure of the intact 14-subunit human cytochrome c oxidase.

Journal:

Cell Res. 2018 Oct;28(10):1026-1034. doi: 10.1038/s41422-018-0071-1. Epub 2018, Jul 20.

Abstract:

Respiration is one of the most basic features of living organisms, and the electron transport chain complexes are probably the most complicated protein system in mitochondria. Complex-IV is the terminal enzyme of the electron transport chain, existing either as randomly scattered complexes or as a component of supercomplexes. NDUFA4 was previously assumed as a subunit of complex-I, but recent biochemical data suggested it may be a subunit of complex-IV. However, no structural evidence supporting this notion was available till now. Here we obtained the 3.3 A resolution structure of complex-IV derived from the human supercomplex I1III2IV1 and assigned the NDUFA4 subunit into complex-IV. Intriguingly, NDUFA4 lies exactly at the dimeric interface observed in previously reported crystal structures of complex-IV homodimer which would preclude complex-IV dimerization. Combining previous structural and biochemical data shown by us and other groups, we propose that the intact complex-IV is a monomer containing 14 subunits.