Abstract
From infrared linear dichroism studies, direct evidence is given for a new Na DNA form, which is similar to the C form of Li DNA. This C-like form in Na DNA occurs under conditions of very low NaCl content (at high relative humidity), high NaCl content (at low relative humidity), and low G + C content of the DNA (at low relative humitiy). The C form of Li DNA was originally discovered by x-ray diffraction, but has not previously been characterized by infrared spectroscopy. The C form is primarily characterized by the orientation of the O2- -O3 line of the phosphate group, which is about 48° (±2°) with respect to the helical DNA axis and which is different from that of the B and A forms. Na DNA molecules rich in A + T may entirely or partially adopt the C form at low relative humidity. Since from infrared evidence, the C-like form is found not only in Li DNA at low relative humidity but also in Na DNA under different conditions, the C form may be biologically important. A possible role for recognition by proteins is suggested.
Keywords: DNA conformations, infrared linear dichroism, base composition, base sequence
Full text
PDF
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Arnott S., Fuller W., Hodgson A., Prutton I. Molecular conformations and structure transitions of RNA complementary helices and their possible biological significance. Nature. 1968 Nov 9;220(5167):561–564. doi: 10.1038/220561a0. [DOI] [PubMed] [Google Scholar]
- Arnott S., Hukins D. W. Optimised parameters for A-DNA and B-DNA. Biochem Biophys Res Commun. 1972 Jun 28;47(6):1504–1509. doi: 10.1016/0006-291X(72)90243-4. [DOI] [PubMed] [Google Scholar]
- Arnott S. The geometry of nucleic acids. Prog Biophys Mol Biol. 1970;21:265–319. doi: 10.1016/0079-6107(70)90027-1. [DOI] [PubMed] [Google Scholar]
- Bram S. The function of the structure of DNA in chromosomes. Biochimie. 1972;54(8):1005–1011. doi: 10.1016/s0300-9084(72)80051-8. [DOI] [PubMed] [Google Scholar]
- Cooper P. J., Hamilton L. D. The A-B conformational change in the sodium salt of DNA. J Mol Biol. 1966 Apr;16(2):562–563. doi: 10.1016/s0022-2836(66)80193-6. [DOI] [PubMed] [Google Scholar]
- FRASER M. J., FRASER R. D. B. Evidence on the structure of desoxyribonucleic acid from measurements with polarized infra-red radiation. Nature. 1951 May 12;167(4254):761–762. doi: 10.1038/167761a0. [DOI] [PubMed] [Google Scholar]
- Florentiev V. L., Ivanov V. I. RNA polymerase: two-step mechanism with overlapping steps. Nature. 1970 Nov 7;228(5271):519–522. doi: 10.1038/228519a0. [DOI] [PubMed] [Google Scholar]
- Gennis R. B., Cantor C. R. Optical studies of a conformational change in DNA before melting. J Mol Biol. 1972 Apr 14;65(3):381–399. doi: 10.1016/0022-2836(72)90196-9. [DOI] [PubMed] [Google Scholar]
- MARVIN D. A., SPENCER M., WILKINS M. H., HAMILTON L. D. The molecular configuration of deoxyribonucleic acid. III. X-ray diffraction study of the C form of the lithium salt. J Mol Biol. 1961 Oct;3:547–565. doi: 10.1016/s0022-2836(61)80021-1. [DOI] [PubMed] [Google Scholar]
- Owen R. J., Hill L. R., Lapage S. P. Determination of DNA base compositions from melting profiles in dilute buffers. Biopolymers. 1969;7(4):503–516. doi: 10.1002/bip.1969.360070408. [DOI] [PubMed] [Google Scholar]
- Pilet J., Brahms J. Dependence of B-A conformational change in DNA on base composition. Nat New Biol. 1972 Mar 29;236(65):99–100. doi: 10.1038/newbio236099a0. [DOI] [PubMed] [Google Scholar]
- Rudner R., Ledoux M., Mazelis A. Distribution of pyrimidine oligonucleotides in strands L and H of Bacillus subtilis DNA. Proc Natl Acad Sci U S A. 1972 Sep;69(9):2745–2749. doi: 10.1073/pnas.69.9.2745. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Yamagishi H., Takahashi I. Heterogeneity in nucleotide composition of Bacillus subtilis DNA. J Mol Biol. 1971 Apr 28;57(2):369–371. doi: 10.1016/0022-2836(71)90355-x. [DOI] [PubMed] [Google Scholar]