Biomedical Engineering Reference
In-Depth Information
a
b
40
YF 11
YF-11
30
Y6
20
YPWF
10
0
YPFF
YPWG
c
100
YFF
10
YPF
1
WW
0.1
300 ms
Fig. 13.8 Effect of peptide length and structure on the transport of peptides through a single
(M113Y)
7
pore. (a) Representative single-channel traces; (b) Current blockage amplitudes; and
(c) Event mean dwell times. The experiments were performed under a series of symmetrical buffer
conditions with a 2.0 mL solution comprising 1 M NaCl, and 10 mM Tris-HCl (pH 7.5) at +50 mV
(
cis
at ground). Peptides were added to the
trans
compartment, while the (M113Y)
7
protein was added
from
cis
of the chamber device. The final concentrations of peptides in the buffer were 1.0
m
Meach.
Figure reprinted with permission from [
3
]. Copyright 2009 American Chemical Society
differentiated from each other based on the different blockage residual currents and
mean residence times of their events produced in the (M113F)
7
pore [
3
].
The finding is significant in that a promising peptide/protein sequencing method
could be visualized. For example, long peptides or protein molecules can be
cleaved into short fragments by enzymatic digestion or chemical cleavage. And
then, the identities (e.g., structure and sequence) of these short peptide fragments
can be determined by examining their translocation in the engineered protein pores
with weak non-covalent binding sites. This concept has been demonstrated by
real-time monitoring trypsin cleavage of the amyloid-
) in the
(M113F)
7
protein pore [
61
]. As shown in Fig.
13.9
, before addition of trypsin to
the peptide A-
b
peptide (A-
b
(10-20) solution, only a single type of current blockage events was
observed. In contrast, after addition of trypsin, two new types of current modulation
events with different residence times and amplitudes from those of peptide A-
b
b
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