Artificial nuclease, activity

This system has also been shown to be dependent on the secondary structure of DNA, the A, B, and Z forms reacting at different rates [150]. The likely explanation is that the faster reacting B DNA forms a more stable complex with the catalyst. This artificial DNase activity has also been compared with cleavage by micrococcal nuclease, and shown to recognize the same sites but not all those cleaved by DNase 1, again implying some local conformational preferences [151]. Chromatin structure has also been probed [152]. 

Another class of promising new generation nucleases includes artificial and semiartificial nucleases. Chemical nucleases are typical artificial nucleases that make use of redox-active compounds (e.g., phenanthroline-copper and ferrous-EDTA) as the cutter and an attached oligonucleotide as the site-specific recognition module. Although the importance of chemical nucleases and the potential for their applications are bound to grow, this chapter focuses on some of the classical enzyme nucleases that are most widely used in recombinant DNA technology. 

The guanidinium unit plays a crucial role in the activity of some enzymes such as staphylococcal nuclease [23] and has been used as an activating and/or anchoring group in the design of supramolecular catalysts [24-28]. Artificial phosphodiesterases 27 30 were developed by introducing from two to four guanidinium units at the upper rim of a cone calix[4]arene scaffold [26]. 

---