Abstract
A graphical formula is presented for determining the base ratio of melted DNA. By use of this formula, the composition of sequences which melt in different portions of the melting curves of Clostridium DNA, Escherichia coli DNA, and mouse DNA were determined. As the DNA melts, the per cent of adenine and thymine (AT) in the melted sequences decreases linearly with temperature. The average composition of sequences which melt in a given part of the melting curve is proportional to the base ratio of the DNA. The concentration and average composition of sequences were determined for three parts of the melting curves of the DNA samples, and a frequency distribution curve was constructed. The curve is symmetrical and has a maximum at about 56% AT. The distribution of GC-rich sequences on the E. coli chromosome was estimated by shearing, partially melting, and fractionating the DNA on hydroxylapatite. GC-rich sequences appear to occur every thousand base pairs, and have a maximum length of about 180 base pairs. The graphical formula was applied to the determination of the composition of sequences which melt in different parts of the melting curve of chromatin. Throughout the melting curve, the composition of the melting sequences is about 60% AT, which appears to suggest that relatively long sequences are melting simultaneously. Their melting temperature may be a function of the composition of the protein on different parts of the DNA. The problem of light scattering in DNA-protein and DNA was also investigated. A formula is presented which corrects for light scattering by relating the intensity of the scattered light to the rate of change of absorbance of DNA with wavelength.
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Selected References
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- BURTON K. A study of the conditions and mechanism of the diphenylamine reaction for the colorimetric estimation of deoxyribonucleic acid. Biochem J. 1956 Feb;62(2):315–323. doi: 10.1042/bj0620315. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Bernardi G. Chromatography of nucleic acids on hydroxyapatite. Nature. 1965 May 22;206(4986):779–783. doi: 10.1038/206779a0. [DOI] [PubMed] [Google Scholar]
- Blobel G., Potter V. R. Nuclei from rat liver: isolation method that combines purity with high yield. Science. 1966 Dec 30;154(3757):1662–1665. doi: 10.1126/science.154.3757.1662. [DOI] [PubMed] [Google Scholar]
- COMMERFORD S. L., HUNTER M. J., ONCLEY J. L. The preparation and properties of calf liver deoxyribonucleoprotein. J Biol Chem. 1963 Jun;238:2123–2134. [PubMed] [Google Scholar]
- FELSENFELD G., SANDEEN G. The dispersion of the hyperchromic effect in thermally induced transitions of nucleic acids. J Mol Biol. 1962 Dec;5:587–610. doi: 10.1016/s0022-2836(62)80088-6. [DOI] [PubMed] [Google Scholar]
- Felsenfeld G., Hirschman S. Z. A neighbor-interaction analysis of the hypochromism and spectra of DNA. J Mol Biol. 1965 Sep;13(2):407–427. doi: 10.1016/s0022-2836(65)80106-1. [DOI] [PubMed] [Google Scholar]
- GEIDUSCHEK E. P. "Reversible" DNA. Proc Natl Acad Sci U S A. 1961 Jul 15;47:950–955. doi: 10.1073/pnas.47.7.950. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Goel N. S. A semi-empirical analysis of the melting curves of synthetic DNA molecules and the calculation of the stacking and pairing energies and entropies in DNA. J Theor Biol. 1968 Mar;18(3):350–370. doi: 10.1016/0022-5193(68)90083-0. [DOI] [PubMed] [Google Scholar]
- Goel N. S., Montroll E. W. Denaturation and renaturation of DNA. II. Possible use of synthetic periodic copolymers to establish model and parameters. Biopolymers. 1968;6(5):731–765. doi: 10.1002/bip.1968.360060509. [DOI] [PubMed] [Google Scholar]
- Hirschman S. Z., Felsenfeld G. Determination of DNA composition and concentration by spectral analysis. J Mol Biol. 1966 Apr;16(2):347–358. doi: 10.1016/s0022-2836(66)80178-x. [DOI] [PubMed] [Google Scholar]
- LOWRY O. H., ROSEBROUGH N. J., FARR A. L., RANDALL R. J. Protein measurement with the Folin phenol reagent. J Biol Chem. 1951 Nov;193(1):265–275. [PubMed] [Google Scholar]
- MAHLER H. R., KLINE B., MEHROTRA B. D. SOME OBSERVATIONS ON THE HYPOCHROMISM OF DNA. J Mol Biol. 1964 Sep;9:801–811. doi: 10.1016/s0022-2836(64)80186-8. [DOI] [PubMed] [Google Scholar]
- MARMUR J., DOTY P. Determination of the base composition of deoxyribonucleic acid from its thermal denaturation temperature. J Mol Biol. 1962 Jul;5:109–118. doi: 10.1016/s0022-2836(62)80066-7. [DOI] [PubMed] [Google Scholar]
- Montroll E. W., Goel N. S. Denaturation and renaturation of DNA. I. Equilibrium statistics of copolymeric DNA. Biopolymers. 1966 Sep;4(8):855–886. doi: 10.1002/bip.1966.360040805. [DOI] [PubMed] [Google Scholar]
- Olins D. E., Olins A. L., Von Hippel P. H. On the structure and stability of DNA-protamine and DNA-polypeptide complexes. J Mol Biol. 1968 Apr 14;33(1):265–281. doi: 10.1016/0022-2836(68)90293-3. [DOI] [PubMed] [Google Scholar]
- Russell A. P. The invertebrate acid deoxyribonucleases and molecular taxonomy. Comp Biochem Physiol. 1966 Aug;18(4):961–969. doi: 10.1016/0010-406x(66)90227-1. [DOI] [PubMed] [Google Scholar]
