OXIDOREDUCTASE, CONFORMATIONAL CHANGES, CYANIDE BINDING, CELL MEMBRANE, COPPER, ELECTRON TRANSPORT, HEME, HYDROGEN ION TRANSPORT, ION TRANSPORT, IRON, MEMBRANE, METAL-BINDING, RESPIRATORY CHAIN, TRANSMEMBRANE, TRANSPORT 3FYI CATALYTIC CORE SUBUNITS (I AND II) OF CYTOCHROME C OXIDASE FROM RHODOBACTER SPHAEROIDES IN THE REDUCED STATE BOUND WITH CYANIDE