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Condensation of DNA by multivalent cations: Considerations on mechanism by Victor A. Bloomfield is a Biochemistry, Genetics and Molecular Biology article available to read on EtoBox.

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DNA is generally found within viruses and cells in a tightly packaged state, typically occupying only 10-4-10-6 of the volume of the uncondensed DNA wormlike coil. Condensation can be induced in vitro at low salt by the naturally occurring polyamines spermidine3+ and spermine4+, by hexammine cobalt (111) , and even by Mg2+ in methanol-water mixtures. These condensates generally have an orderly, toroidal, or rodlike shape and size similar to that of DNA gently lysed from phage heads. It is also striking that the condensate size distribution is independent of DNA molecular length from 400 to 40,000 base pairs (bp) , but that shorter DNA molecules (e.g., 150-bp mononucleosomal DNA) cannot condense in this fashion. We have constructed a successive association equilibrium theory to attempt to explain these results, using an equation devised by Tanford for micelle formation. Most of the obvious attractive and repulsive free energy contributions (mixing, bending, hydration, and other nearest-neighbor interactions) are linear in the amount of DNA incorporated, but the net attractive AGO grows nonlinearly because of the increasing average number of nearest neighbors of each duplex as the pa

Who reads Condensation of DNA by multivalent cations: Considerations on mechanism?

Author

Victor A. Bloomfield

Publisher

Wiley (John Wiley & Sons); John Wiley & Sons Inc.; Wiley (ISSN 0006-3525)

Published

1991

Language

EN

Field

Biochemistry, Genetics and Molecular Biology (Life Sciences)