It has been widely accepted that precise and detailed understanding of bioreactions and biosystems, as well as the resultant full utilization of them, are quite important for further progresses of biotechnology, molecular biology, and other relevant fields. However, these problems are hardly solved as long as one uses only biological means. Prof. Makoto Komiyama recognized these facts long time ago and started to apply various chemical approaches to these problems. As the results, he designed and prepared many kinds of man-made chemical tools which carry out what naturally occurring enzymes cannot. With the use of these new tools, he has envisioned new biotechnology which overcomes the limitations of current technology. The following is brief summary of the works of Prof. Komiyama.

1. Molecular design and preparation of super restriction enzymes for site-selective scission of huge DNA One of the most important achievements of Prof. Komiyama is the preparation of gsuper restriction enzymesh for site-selective scission of huge DNA, and their applications to genome manipulation and engineering. Although naturally occurring restriction enzymes are sufficient to manipulate small DNA such as plasmid, the canonical sequences of these natural tools are too short when they are compared with the sizes of genomes. Thus, they cut genome DNA at too many sites and cannot be used for genome manipulation. Accordingly, artificial new tools which can cut huge DNA at any predetermined site (gsuper restriction enzymesh) are absolutely required. The importance of these tools has been well recognized for a long time by many researchers in the world, but no successes have ever been reported.
Under these situations, Prof. Komiyama succeeded in the preparation of super restriction enzymes. He first found a catalyst which efficiently hydrolyzes enormously stable phosphodiester linkages in DNA. Then this catalyst was combined with synthetic polymer which binds to target site of DNA substrate, resulting in targeted site-selective scission of DNA. This super restriction enzyme is the first (and the sole so far reported) man-made tool which can cut huge DNA at any predetermined site. He further showed that the super restriction enzymes are useful to cut human genome at desired site, to carry out versatile DNA manipulation which is hard to achieve by using naturally occurring enzymes, and also to convert target gene to another form in human cells.
The super restriction enzymes are composed of (i) two strands of peptide nucleic acid (PNA) which invade the substrate double-stranded DNA at the target site and (ii) Ce(IV)/EDTA complex which hydrolyzes the target site. Here, PNA is a DNA analog having peptide backbone in place of phosphodiester linkage and very strongly binds to DNA by Watson-Crick rule. There are two important key points in the elegant molecular design by Prof. Komiyama. First, the binding sites of these two PNA strands in the substrate DNA were laterally shifted each other by several nucleobases. As the result, single-stranded portions were formed at predetermined site in each of the double-strands of substrate DNA. Secondarily, a monophosphate as a ligand was attached to each of the PNA strands to recruit the Ce(IV)/EDTA complex at the target scission site. The Ce(IV)/EDTA intrinsically hydrolyzes only single-stranded DNA because of its unique substrate-specificity, so that the single-stranded portions in both strands of the DNA, formed by the invasion of these two PNA strands, are selectively hydrolyzed. The site of selective scission of the super restriction enzymes is freely modulated by changing the sequences and lengths of the PNA strands, and thus even huge DNA can be site-selectively hydrolyzed at predetermined site.

2. Manipulation of huge DNA using the super restriction enzyme
By using the super restriction enzymes, Prof. Komiyama successfully cut the whole human genome at one predetermined site. Importantly, off-target scission never occurred even when these sequences were only marginally different from the target sequence. Again, this is the first success of site-selective scission of genome by man-made chemical tools. Furthermore, by using these new tools, he promoted homologous recombination (intrinsic repair systems of human beings) and effectively converted a target gene to desired form in the human cells. In typical experiments, target site in a gene was cut by using appropriately designed super restriction enzyme, and a donor DNA fragment having a similar but slightly different sequence was added thereto. In homologous recombination in the human cells, the scission site was repaired with the use of the donor DNA as template and thus the corresponding sequence in the original gene was converted to the sequence of the donor DNA. The super restriction enzymes can selectively cut human genome at any site, and choice of donor DNA is free. Thus, this technology should have a strong potential for alteration of malignant gene to normal gene, knockout of any unnecessary gene, and others.

3. Preparation of other tools essential for future biotechnology
In addition to the super restriction enzymes, Prof. Komiyama prepared various tools which are valuable to clarify the mechanisms of biological reactions and also transform a number of biomaterials to desired forms. For example, he analyzed human telomere by using chemical means and, based on the molecular information obtained, prepared new tools to transform human telomeres. He also developed many other artificial enzymes, sensors, artificial receptors.
As described here, Prof. Komiyama prepared various chemical tools to analyze bioreactions and biosystems, and developed new biotechnology. The design and preparation of the super restriction enzymes, as well as developments of new genome manipulation technology using them, are especially noteworthy. All of these works have been originated from his own ideas, and highly evaluated in the world. Accordingly, it has been concluded that the achievements of Prof. Komiyama are qualified for the Chemical Society of Japan Award for 2011.