Chemistry Reference
In-Depth Information
14
New Metallo - DNA zymes :
Fundamental Studies of Metal- DNA
Interactions and Metal
Sensing Applications
Zehui Cao and Yi Lu
14.1 Introduction
DNA was long considered only a carrier of genetic information. In 1994, Breaker
and Joyce discovered that DNAs isolated using a combinatorial chemistry approach
called
in vitro
selection,
1 - 5
were also able to carry out catalytic activities.
1
Since then,
many catalytic DNA molecules, termed deoxyribozymes or DNAzymes, have been
reported. Being the latest member of the enzyme family after protein and RNA
enzymes, DNAzymes have rapidly demonstrated their capability of catalysing a
variety of reactions previously known to only ribozymes or protein enzymes,
6 - 9
including RNA/DNA cleavage,
1,10 - 16
ligation,
17 - 19
phosphorylation,
18,20
cleavage of
phosphoramidate bonds
21
and porphyrin metallation.
22
Figure 14.1 shows a few
examples of DNAzymes. In addition, DNAzymes have shown catalytic effi ciencies
comparable to those of ribozymes or protein enzymes. For example, the '10-23'
DNAzyme identifi ed by Santoro and Joyce has an observed catalytic effi ciency of
10
9
M
− 1
min
− 1
.
15
Unlike RNA and protein enzymes, DNAzymes have not been found
in nature, and
in vitro
selection remains the primary way to isolate and identify
new DNAzymes.
