## Abstract We have measured the binding equilibria of proflavin to T2L bacteriophage, in both βslowβ and βfastβ sedimenting forms, and to free T2L DNA. Measurements were carried out by difference spectroscopy at 430 nm at temperatures from 13 to 43Β°C and at pH 5.6 and 7.6. We found no significant
Effect of Mg++ and polyamines on proflavine binding to T2 DNA
β Scribed by Steven C. Riemer; Victor A. Bloomfield
- Publisher
- Wiley (John Wiley & Sons)
- Year
- 1979
- Tongue
- English
- Weight
- 740 KB
- Volume
- 18
- Category
- Article
- ISSN
- 0006-3525
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β¦ Synopsis
Abstract
Proflavine binding may be used as a probe of the environment and interactions of DNA. In this paper we report the effects of the divalent cations Mg^++^ and putrescine and the trivalent cation spermidine on the proflavineβNa DNA binding equilibrium. Difference spectroscopy at 430 nm was used to determine apparent proflavineβDNA binding constants K at several concentrations of each cation for temperatures between 15 and 43Β°C, and at a constant total ionic strength of 0.1__M__. Mg^++^, putrescine, and spermidine all have greater effects on K than expected on the basis of ionic strength alone in the order spermidine > Mg^++^ β³ putrescine. van't Hoff analysis of K(T) enabled calculation of Ξ__H__Β° and Ξ__S__Β°, which are affected differently by each cation. These differences are discussed qualitatively in terms of such concepts as release of condensed counterions, localized or unlocalized condensation, hydration, and restriction of molecular and internal rotation.
π SIMILAR VOLUMES
## Abstract We have measured the kinetics of proflavin binding to Tβeven bacteriophagesβthe 700 S and 1000 S forms of T2L, T4D, and T4D os41βby difference spectroscopy at 430 nm. Measurements were carried out from 22Β° to 37Β°C. Binding is very slow to encapsulated DNA compared to free DNA, requiring
## Abstract Experimental binding isotherms relative to the interactions between proflavine and poly(A) or DNA are analyzed by comparison with theoretical models dealing with competitive cooperative bindings. In the case of poly(A), there are apparently no specific binding sites for the positive co
Seven new steroidal polyamines derived from bile acids, either lithocholic or deoxycholic acid, have been studied as DNA-binding agents using four complimentary methods: an ethidium displacement assay, observed changes in the thermal denaturation of poly[d(AT)], effects on hyperchromicity of DNA, an
The interaction of Mg2+, Ca2+, Zn2+, and Cd2' with calf thymus DNA has been investigated by Raman spectroscopy. These spectra reveal that all of these ions, and particularly Zn2+, bind to phosphate groups of DNA, causing a slight structural change in the polynucleotide at very small metal : D N A (
In order to study the effect of glucose substitution on the sedimentation velocitiea of the T-even phage DNA's, T2 and T2\*, and T6 and T6\* bacteriophages were grown with H3 and Paz labeling. Zone sedimentation of the DNA's isolated from these phages showed that the glucosylated DNA's from both T2