Biology Reference
In-Depth Information
Figure 1.6 GsGCS globin-domain bis-histidyl coordination involves proximal HisF8 and
distal HisE11 (dark grey, PDB: 2W31). Such an unprecedented coordination causes the
E-helix in a 30
anticlockwise rotation when compared to SwMb (light grey, PDB: 1MBN),
as indicated with the black arrow in the figure.
et al., 2010; Pesce et al., 2009
). Such a bis-histidyl coordination is unprec-
edented, as it usually involves His residues at topological position F8 and E7
at proximal and distal positions, respectively. This special coordination
forces the E-helix in a 30
anticlockwise rotation (relative to
Sw
Mb)
(
Fig. 1.6
). This rotation results in an orthogonal orientation of the
E-helix to the C-helix and almost parallel to the haem group, thus reshaping
the haem distal cavity (
Pesce et al., 2009
).
2.5. Non-haem globin sensors
The discovery of non-haem globins confirms the high dynamicity and
adaptability of this protein fold. Non-haem chimeric globins represent an
emerging sensor group that might disclose a big number of variations
and specializations.
2.5.1 The B. subtilis
s
B regulator
B. subtilis
is capable of reacting against environmental stress via the
stressosome. The
B. subtilis
stressosome is a 1.5-MDa complex that trans-
duces environmental signals, thus mediating the stress response of the