Chemistry and Chemical Biology ETDs

DaWen Ding

Publication Date

12-8-1977

Abstract

The binding of Hg(II) and Ag(I) to the bases of DNA and polynucleotides induces strong absorption and CD bands. From electric dichroism studies, the transition moment of the difference absorption band at 293 nm is in the plane of the bases and has a huge negative CD band at 285 nm; while the corresponding 293 nm difference absorption band of DNA-Ag(I) complex is relatively CD inactive. A second band at 270 nm in the difference absorption spectrum of the DNA-Ag(I) complex has a large associated CD band at 270 nm. This transition is out of the plane of the bases. From a nearest neighbor matrix analysis of the heavy metal ions CD perturbation, the G containing first nearest neighbors are perturbed the most. The preferential binding of Hg(II) to the TpA first neighbor and the resultant CD perturbation has been explained by a B form to A form conformational change. The increase of the sedimentation coefficients of the rigid rod sonicated DNA and the globular core particle of the nucleosome by the heavy metal ions can be accounted for by the increase of molecular weight and the decrease of the partial specific volume due to the high density of the heavy metal ions. The binding of poly-L-lysine in the minor groove of the DNA helix does not affect the binding of Hg(II) to the major groove. The buried DNA in the wrapping of the core particle of the nucleosome is inaccesible to heavy metal ions and 60 to 80% of the total DNA in the core particle is involving in the wrapping. Either a charge transfer band between the bases and the heavy metal ions or a perturbation theory of the bases by the heavy metal ions would explain satisfactorily the experimental optical results of DNA-Hg(II) and DNA-Ag(I) complexes.

DNA-Hg(II) and DNA-Ag(!) Complexes.

Difference Absorption, CD, Electric Dichroism, and Sedimentation Velocity.

Poly-L-lysine-DNA Complexes and Nucleosome.

Language

English

Document Type

Dissertation

Degree Name

Chemistry

Level of Degree

Doctoral

Department Name

Department of Chemistry and Chemical Biology

First Committee Member (Chair)

Fritz Schreyer Allen

Second Committee Member

Edward A. Walters

Third Committee Member

Richard Willis Holder

Fourth Committee Member

David Lee Vander Jagt

Fifth Committee Member

William Fletcher Coleman

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