DNA biology

Biodistribution analysis is conducted at the molecular level. The current gold standard is a quantitative polymerase chain reaction (Q-PCR) assay that detects the number of vector copies per microgram of genomic DNA. Biological fluids and tissue samples are carefully harvested (to avoid crosscontamination) from control and gene therapy product-injected animals at... 

Enzymatic Cleavage of DNA Biological Role and Application to Sequence Analysis... 

Interactions between macromolecules (protems, lipids, DNA,.. . ) or biological structures (e.g. membranes) are considerably more complex than the interactions described m the two preceding paragraphs. The sum of all biological mteractions at the molecular level is the basis of the complex mechanisms of life. In addition to computer simulations, direct force measurements [98], especially the surface forces apparatus, represent an invaluable tool to help understand the molecular interactions in biological systems. 

There are, indeed, many biological implications that have been triggered by the advent of fullerenes. They range from potential inhibition of HIV-1 protease, synthesis of dmgs for photodynamic therapy and free radical scavenging (antioxidants), to participation in photo-induced DNA scission processes [156, 157, 158, 159, 160, 161, 162 and 163]. These examples unequivocally demonstrate the particular importance of water-soluble fullerenes and are summarized in a few excellent reviews [141, 1751. 

Lewis F D, Wu T F, Zhang Y F, Letsinger R L, Greenfieid S R and Wasieiewski M R 1997 Science 277 673-6 Keiiey S O and Barton J K 1999 Eiectron transfer between bases in doubie heiicai DNA Science 283 375-81 Beratan D N, Priyadashy S and Risser S M 1997 Chemistry and Biology 4 3-8... 

Ivanov, V.I., Minchenkova, L.E., Minyat, E.E., Schyolkina, A.K. Cooperative transitions in DNA with no separation of strands. Cold Spring Harbor Symposia on Quantitative Biology 47 (1983) 243-250... 

Packer M J, M P Dauncey and C A Hunter 2000. Sequence-dependent DNA Structure Dinucleotide Conformational Maps. Journal of Molecular Biology 295 71-83. 

The final class of methods that we shall consider for calculating the electrostatic compone of the solvation free energy are based upon the Poisson or the Poisson-Boltzmann equatior Ihese methods have been particularly useful for investigating the electrostatic properties biological macromolecules such as proteins and DNA. The solute is treated as a body of co stant low dielectric (usually between 2 and 4), and the solvent is modelled as a continuum high dielectric. The Poisson equation relates the variation in the potential (f> within a mediu of uniform dielectric constant e to the charge density p ... 

The furanose rings of the deoxyribose units of DNA are conformationally labile. All flexible forms of cyclopentane and related rings are of nearly constant strain and pseudorotations take place by a fast wave-like motion around the ring The flexibility of the furanose rings (M, Levitt, 1978) is presumably responsible for the partial unraveling of the DNA double helix in biological processes. 

In biological systems molecular assemblies connected by non-covalent interactions are as common as biopolymers. Examples arc protein and DNA helices, enzyme-substrate and multienzyme complexes, bilayer lipid membranes (BLMs), and aggregates of biopolymers forming various aqueous gels, e.g, the eye lens. About 50% of the organic substances in humans are accounted for by the membrane structures of cells, which constitute the medium for the vast majority of biochemical reactions. Evidently organic synthesis should also develop tools to mimic the Structure and propertiesof biopolymer, biomembrane, and gel structures in aqueous media. 

Benzene oxide and compounds derived from it are carcinogenic and can react with DNA to induce mutations This difference m the site of biological oxidation—ring versus side chain—seems to be responsible for the fact that benzene is carcinogenic but toluene is not... 

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