Structure and stability of sodium and potassium complexes of dT4G4 and dT4G4T

Min Lu, Qiu Guo, Neville R. Kallenbach

Research output: Contribution to journalArticle

Abstract

The ends of eukaryotic chromosomes contain specialized structures that include DNA with multiple tandem repeats of simple sequences containing clusters of G on one strand, together with proteins which synthesize and bind to these sequences. The unit repeat in the protozoan Oxytricha with the cluster dT4G4 can form structures containing tetrads of guanine residues, referred to G4 DNA, in the presence of metal ions such as Na+ or K+. We show here that, in the presence of Na+, dT4G4 forms a tetramer with parallel strands by means of a UV cross-linking assay. In the presence of K+, two further interactions are observed: at low temperature, higher order complexes are formed, provided the 3′ end of the strand is G; a single 3′T inhibits this association in dT4G4T. At high temperature, these complexes dissociate, leading to a tetramer with a different ordered structure that melts only at very high temperatures. These results suggest that the cohesive properties of DNA containing G clusters might depend on associative interactions driven by a free 3′G terminus in the presence of K+, as well as by connecting antiparallel G hairpins as has been postulated.

Original languageEnglish (US)
Pages (from-to)2455-2459
Number of pages5
JournalBiochemistry
Volume31
Issue number9
StatePublished - 1992

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Potassium
Sodium
Temperature
DNA
Oxytricha
Tandem Repeat Sequences
Guanine
Chromosomes
Metal ions
Assays
Metals
Association reactions
Ions
Proteins

ASJC Scopus subject areas

  • Biochemistry

Cite this

Lu, M., Guo, Q., & Kallenbach, N. R. (1992). Structure and stability of sodium and potassium complexes of dT4G4 and dT4G4T. Biochemistry, 31(9), 2455-2459.

Structure and stability of sodium and potassium complexes of dT4G4 and dT4G4T. / Lu, Min; Guo, Qiu; Kallenbach, Neville R.

In: Biochemistry, Vol. 31, No. 9, 1992, p. 2455-2459.

Research output: Contribution to journalArticle

Lu, M, Guo, Q & Kallenbach, NR 1992, 'Structure and stability of sodium and potassium complexes of dT4G4 and dT4G4T', Biochemistry, vol. 31, no. 9, pp. 2455-2459.
Lu, Min ; Guo, Qiu ; Kallenbach, Neville R. / Structure and stability of sodium and potassium complexes of dT4G4 and dT4G4T. In: Biochemistry. 1992 ; Vol. 31, No. 9. pp. 2455-2459.
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