Monovalent cation induced structural transitions in telomeric DNAs: G-DNA folding intermediates

Journal Article · Tue May 07 04:00:00 EDT 1991 · Biochemistry; (United States)

DOI:https://doi.org/10.1021/bi00232a013· OSTI ID:5393126

Hardin, C C; Watson, T ^[1]; Henderson, E ^[2]; Prosser, J K ^[3]

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1. North Carolina State Univ., Raleigh (USA)
2. Iowa State Univ., Ames (USA)
3. Univ. of California, Berkeley (USA)

Telomeric DNA consists of G- and C-rich strands that are always polarized such that the G-rich strand extends past the 3{prime} end of the duplex to form a 12-16-base overhang. These overhanging strands can self-associate in vitro to form intramolecular structures that have several unusual physical properties and at least one common feature, the presence of non-Watson-Crick G{center dot}G base pairs. The term G-DNA was coined for this class of structures. On the basis of gel electrophoresis, imino proton NMR, and circular dichroism (CD) results, the authors find that changing the counterions from sodium to potassium specifically induces conformational transitions in the G-rich telomeric DNA from Tetrahymena, d(T{sub 2}G{sub 4}){sub 4} (TET4), which results in a change from the intramolecular species to an apparent multistranded structure, accompanied by an increase in the melting temperature of the base pairs of >25{degree}, as monitored by loss of the imino proton NMR signals. They infer that the multistranded structure is a quadruplex. The results indicate that specific differences in ionic interactions can result in a switch in telomeric DNAs between intramolecular hairpin-like or quadruplex-containing species and intermolecular quadruplex structures, all of which involve G{center dot}G base pairing interaction. They propose a model in which duplex or hairpin forms of G-DNA are folding intermediates in the formation of either 1-, 2-, or 4-stranded quadruplex structures.

• DOE Contract Number: FG03-86ER60406
• OSTI ID: 5393126
• Journal Information: Biochemistry; (United States), Journal Name: Biochemistry; (United States) Vol. 30:18; ISSN 0006-2960; ISSN BICHA
• Country of Publication: United States
• Language: English

Related Subjects

550201 -- Biochemistry-- Tracer Techniques
550401* -- Genetics-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ANIMALS
CILIATA
DICHROISM
INVERTEBRATES
ISOTOPES
LIGHT NUCLEI
MAGNETIC CIRCULAR DICHROISM
MAGNETIC RESONANCE
MICROORGANISMS
MOLECULAR STRUCTURE
NUCLEAR MAGNETIC RESONANCE
NUCLEI
NUCLEIC ACIDS
ODD-EVEN NUCLEI
OLIGONUCLEOTIDES
ORGANIC COMPOUNDS
PHOSPHORUS 31
PHOSPHORUS ISOTOPES
PROTOZOA
RESONANCE
STABLE ISOTOPES
STRUCTURE-ACTIVITY RELATIONSHIPS
TETRAHYMENA