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Figure 7.
Figure 7. Stereo view of the final (2F[o] - F[c]) electron
density map showing the network of bonds that bridge the two
pairs of heme groups in an SCC-A molecule (see the text and
[Gouet et al 1995]). Heme groups and residues Asn60, Arg61,
Asp357, together with four water molecules and two sulphate ions
are also shown inside the density. The four subunits participate
in each one of these heme-heme connections. Density for the
azide molecules, situated in the heme distal pockets and
coordinated with the iron atoms, can also be seen in this
drawing. Sulfate ions are located on the molecular 2-fold axis
P. The quality of the electron density allows to define
unambiguously the hand of the heme group from the disposition of
methyl and vinyl groups. For clarity only density situated till
about 2.5 Å from the atoms represented is shown.
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