Cytochrome Oxidase from Paracoccus Denitrificans:
Iwata et al Nature 376 660-669 (1995).
Courtesy of So IWATA.
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Side View of Complete Enzyme
From left to right we have:
Subunit III (in blue) with an embedded phospholipid.
Subunit IV (green, unique to this enzyme)
Subunit I (yellow)
Subunit II (purple)
Antibody fragment (cyan) used to drive crystallization.
Top View of Full Enzyme emphasizinhg helices and beta strands
Helices and strands are identified by Roman and Arabic numerals respectively.
Color Code is :
Subunit III: blue.
Subunit IV: green.
Subunit I: yellow.
Subunit II: purple.
Antibody fragment is omitted.
All of Subunit II showing the two transmembrane helices
Upper Portion of Subunit II emphasizing beta strands
The Copper A Center in subunit II
All of Subunit I from Side
The main features are 11 transmembrane helices, 1 interupted helix (VII)
and two helical connections (III-IV) and (IX-X) lying on the
membrane surface. Heme a is red, Heme a3 is cyan and CuB is blue.
A schematic of the 28 TM helices of bovine enzyme;
note the unusual arrangement in subunit I which resemble
Subunit I from Top: Compare with the schematic above
The environment of cytochrome a
The Cytochrome a3-CuB Binuclear center