A-T and C-C sup + base pairs can form simultaneously in a novel multistranded DNA complex

Journal Article · Mon Jan 22 23:00:00 EST 1990 · Biochemistry; (USA)

DOI:https://doi.org/10.1021/bi00455a033· OSTI ID:6710309

Edwards, E L; Patrick, M H; Gray, D M ^[1]; Fatliff, R L ^[2]

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1. Univ. of Texas, Dallas (USA)
2. Los Alamos National Lab., NM (USA)

Previous experiments have established that in certain synthetic oligomeric DNA sequences, including mixtures of d(AACC){sub 5} with d(CCTT){sub 5}, adenine-thymine (A{center dot}T) base pairs form to the exclusions of neighboring protonated cytosine-cytosine (C{center dot}C{sup +}) base pairs. In the present work, circular dichroism and other measurements were used to study DNA oligomers that represented two additional classes with respect to the formation of A{center dot}T and/or C{center dot}C{sup +} base pairs. (1) One class included two sets of repeating pentameric DNA sequences, d(CCAAT){sub 3-6} and d(AATCC){sub 4,5}. Spectral data showed that as few as 40% C{center dot}C{sup +} base pairs were stable in two sets of oligomers in which A{center dot}T base pairs did not form adjacent to, or in place of, C{center dot}C{sup +} base pairs. (2) Another class of oligomer was represented by d(C{sub 4}A{sub 4}T{sub 4}C{sub 4}), which was studied by CD, HPLC, and centrifugation experiments. This sequence was able to form both types of base pairs as the pH and temperature were lowered. The authors suggest that those sequences that formed only A{center dot}T base pairs had an antiparallel-strand orientation while those that formed only C{center dot}{sup +} base pairs probably had a parallel-strand orientation. They propose that d(C{sub 4}A{sub 4}T{sub 4}C{sub 4}) at low pH adopted a multistranded structure that contained both parallel-stranded C{center dot}C{sup +} base pairs and antiparallel-stranded A{center dot}T base pairs.

• OSTI ID: 6710309
• Journal Information: Biochemistry; (USA), Journal Name: Biochemistry; (USA) Vol. 29:3; ISSN 0006-2960; ISSN BICHA
• Country of Publication: United States
• Language: English

Related Subjects

550200* -- Biochemistry
59 BASIC BIOLOGICAL SCIENCES
AMINES
AROMATICS
AZAARENES
AZINES
BARYONS
CYTOSINE
DICHROISM
DNA
DNA SEQUENCING
ELEMENTARY PARTICLES
FERMIONS
GUANINE
HADRONS
HETEROCYCLIC COMPOUNDS
HYDROXY COMPOUNDS
MAGNETIC CIRCULAR DICHROISM
MOLECULAR STRUCTURE
NUCLEIC ACIDS
NUCLEONS
OLIGONUCLEOTIDES
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORGANIC OXYGEN COMPOUNDS
PROTONS
PURINES
PYRIMIDINES
STRUCTURAL CHEMICAL ANALYSIS
TEMPERATURE EFFECTS