Biology Reference
In-Depth Information
A
h
n
h
n
Elastase
B
3.0
2.0
2.5
1.6
02468
(s)
2.0
1.5
1.0
0
200
Time (s)
400
600
Figure 2.7 Conformational changes in a1-AT on its reaction with elastase, as monitored
by a 3HC probe. The graph A shows the X-ray structures of the free a1-AT and the a1-AT/
elastase complex.
54
The labeled Cys is in yellow. The graph B shows the kinetics of this
conformation transition monitored by our 3HC probe. The inset in this figure presents
the fast part of this transition.
55
confirmed these results but led to much smaller modifications in the
emission spectrum, indicating superiority of the 3HC label in terms of
environment sensitivity. Stopped-flow studies of the reaction between
the labeled
a
1-AT and elastase showed, in addition to the well-described
fast step, a new slow step of the inhibition process
55
that is probably associ-
ated with a slow structural reorganization aimed at stabilizing the final
inhibited complex.
4.2. Peptide
-
nucleic acid interactions
Monitoring interactions of peptides with nucleic acids can be achieved
through a single labeling of the peptide partner with a solvatochromic
dye. However, in this case, solvent sensitivity of these dyes should be opti-
mized for polar environments and remain fluorescent in the DNA complex.
3HC-B fluorophore meets both requirements according to our previous
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