Chemistry Reference
In-Depth Information
7
Artificial Restriction Enzymes As Tools For Future Molecular Biology
and Biotechnology
Yoji Yamamoto and Makoto Komiyama
7.1
Introduction
Today, molecular biology and biotechnology play essential roles in science and indus-
try. These technologies are very simple, but are so powerful that even high-school
students can prepare rather complicated proteins in large amounts without much dif-
ficulty (of course, appropriate guidance should be provided). Furthermore, unexpected
discoveries are being made worldwide almost everyday. Information accumulated by
these studies enables medical and medicinal fields to be more successful and fruitful.
These trends should increase over the next several decades. Unfortunately, almost all
the materials used to date (e.g., enzymes, DNAs, vectors, and cells) are gifts from
Mother Nature, and the contribution of chemists to this technology has not been
very large. However, remarkable developments in bioorganic chemistry and supramo-
lecular chemistry have marked the beginnings of a new epoch.
This chapter describes artificial enzymes that can hydrolyze DNA at the target-site
with desired site-specificity [1]. With these totally man-made tools (artificial restriction
enzymes), even huge DNA can be cut at a predetermined position and used for the
preparation of recombinant DNA. This manipulation is hardly accomplishable as long
as only naturally occurring restriction enzymes are used. Hopefully, these tools will
open the way to new molecular biology and biotechnology in which the DNA of higher
animals and plants can be manipulated.
7.2
Significance of Artificial Restriction Enzymes
Current molecular biology and biotechnology are based on two key processes: (i) site-
selective scission of DNA by restriction enzymes and (ii) recombination of DNA frag-
ments by another enzyme, known as ligase. These methods, first reported in the
1970s, are almost perfect as long as we manipulate small DNA such as the plasmid
DNA of bacteria and genome DNA of virus, which are composed of several thousand
