DNA-processing enzymes

Recently, a quite different model has been proposed that accounts for the appearance of many kinds of mutations, including base pair substitutions, additions and deletions, and small chromosomal mutations of the type that would usually be classified as gene mutations. The model accounts for frequent palindromic sequences (more exactly, imperfect palindromes or quasipalindromes) in DNA that can predispose to alternative DNA structures (e.g., clover leaves) that differ from the usual double helix. The alternative or "secondary" structures can then be acted on by any of a variety of DNA-processing enzymes in ways that may ultimately lead to mutations. The details of these processes are only now becoming manifest, but the general model clearly explains many hitherto mysterious mutational phenomena.371... 

Kuo LY, Liu AH, Marks TJ (1996) Metallocene interactions with DNA and DNA-processing enzymes. Met Ions Biol Syst 33 53-85... 

Effect of Bound Platinum on DNA Processing Enzymes. With some of the effects of platination on DNA structure now defined, we can ask whether and how these changes in DNA conformation will affect enzymes which process DNA. 

Optical tweezers have since been used to stretch and even unwind DNA unfold the tertiary structure of proteins pull on DNA processing enzymes like RNA polymerase as it walks along DNA resist the force produced by viral capsid packaging motors and manipulate entire mammalian cells, sperms and sub-cellular organelles and vesicles. The applications are manifold and the future possibilities are great. 

Using DNA biosensors, two types of DNA-protein interactions can be investigated first, detection of catalytic activity of DNA-processing enzymes such as nucleases, ligases, and pol3mierases and second, affinity interactions of DNA with proteins that can but need not be enzymes. The detection techniques used can be the same as those mentioned above for DNA hybridization sensors. Electroactivity of... 

In addition to forming adducts with DNA, organo-ruthenium(II) complexes have been shown to poison DNA processing enzymes. The ruthe-nium(II) arene compound shown in Fig. 6c poisons topoisomerase II, an important enzyme involved in the processing of DNA to allow the code to be read by the protein making machinery in the cell. These compounds have also been shown to be active against in vitro breast and colon carcinoma cells. 

Kuo L, Li A,Marks T. (1996) Metal ions in biological systems metallocene interactions with DNA and DNA-processing enzymes, Vol. 33. Marcel Dekker, New York. 

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