(A) Ribbon structure
of the SwH-NOX protein from S. woodyi. This figure is a homology model generated in
PyMOL using the solution-state NMR structure of Shewanella
oneidensis(26) (So2144, Protein
Data Bank entry 2KII, chain A). The heme is shown as red sticks. The N- and C-termini
of the protein are denoted. The seven different helices are depicted
in different colors: blue for helix αA, red for helix αB,
hot pink for helix αC, orange for helix αD, gray for helix
αE, purple for helix αF, and chocolate brown for helix
αG. (B) Chemical shift changes for SwH-NOX
upon addition of SwHaCE. The shifts (SwH-NOX to SwH-NOX/SwHaCE), calculated
as {[(ΔN/5)2 + (ΔH)2]/2}1/2, are plotted against the primary
sequence residue number. The cutoff shift was kept at 0.02, and shifts
above 0.02 (dashed line) were considered significant. The secondary
structure of SwH-NOX is shown as a cartoon in which
the rectangles represent α-helices and the solid arrows represent
β-strands. The color code corresponds to the ribbon diagram
in panel A.