Conformational transitions of poly(dA-dT).poly(dA-dT) in ethanolic solutions

Vorlı́čková, Michaela; Sedláček, Pavel; Kypr, Jaroslav; Šponar, J.

doi:10.1093/nar/10.21.6969

Cited by 59 publications

(31 citation statements)

References 28 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Diminution of the absorbance followed, making it impossible to record the corresponding spectrum although no turbidity was detected. If the addition ofCs + was at ooc it was possible to stabilize the novel type X conformation as previously described (24). In this latter case, a gradual increase of the temperature from 0°C to lOoC did not produce any aggregation at all.…”

Section: A Band X Forms Of Poly(da-dt)mentioning

confidence: 61%

Conformational Isomerizations of the Poly(dA-dT) and Poly(amino²dA-dT) Duplexes Involving the Unusual X-DNA Double Helix: A Fourth Derivative Spectrophotometric Study

Garriga

Sági²,

Quintana³

et al. 1990

Journal of Biomolecular Structure and Dynamics

View full text Add to dashboard Cite

Fourth derivative spectrophotometry has been applied to monitor conformational isomerizations of polynucleotides for the first time. The transitions studied have been the B-A and A-X isomerizations of poly(dA-dT) and the B-X one of poly(amino2dA-dT). Parameters obtained from the fourth derivative spectra have been used to follow these conformational changes. The A form of poly(dA-dT) has been characterized by a new fourth derivative peak at 293.0 nm which can be associated to interstrand adenine-adenine interactions. Furthermore, some of the fourth derivative peaks in the long wavelength region (270-310 nm) can be related to stacking interactions present in the polynucleotide double helices. The tentative assignment of these peaks, particularly that at 299.0 nm in the derivative spectra of poly(amino2dA-dT), to n----pi electronic transitions is discussed.

show abstract

Section: A Band X Forms Of Poly(da-dt)mentioning

confidence: 61%

Conformational Isomerizations of the Poly(dA-dT) and Poly(amino²dA-dT) Duplexes Involving the Unusual X-DNA Double Helix: A Fourth Derivative Spectrophotometric Study

Garriga

Sági²,

Quintana³

et al. 1990

Journal of Biomolecular Structure and Dynamics

View full text Add to dashboard Cite

show abstract

“…(14,28). In general, DNA polymers of alternating purine and pyrimidine residues, with the exception of poly(dAT) poly (dTA), have been shown to be capable of forming Z-DNA when chemically modified, under high-salt conditions or when present in supercoiled plasmids (3,14,28,41,42,59,62,64). The possibility of a unique genetic role for d(TG AC),, and other sequences capable of adopting the left-handed helical conformation has been raised 'in several reports suggesting eucaryotic gene conversion and recombination (6,10,21,31,43,51).…”

Section: Resultsmentioning

confidence: 99%

The evolutionarily conserved repetitive sequence d(TG.AC)n promotes reciprocal exchange and generates unusual recombinant tetrads during yeast meiosis.

Treco¹,

Arnheim²

1986

Mol. Cell. Biol.

143

View full text Add to dashboard Cite

We have studied the genetic behavior of the alternating copolymer d(TG AC), inserted into a defined We have previously described an in vivo system for analyzing the ability of specific DNA sequences to engage in homologous meiotic recombination in the yeast Saccharomyces cerevisiae (58). This system was used to demonstrate that different DNA sequences from the human ,B-globin locus participate in genetic exchanges at different frequencies during yeast meiosis. One fragment from the human ,-globin locus, MG-1 (24), was associated with reciprocal exchange during meiosis significantly more frequently than either of two other fragments normally found near MG-1 in the ,-globin cluster. All three sequences lie within an 11-kilobase (kb) region between the human 8-and ,-globin genes that has previously been hypothesized to be a relative hot-spot for genetic exchange within the ,-globin gene cluster (1,18,29).One element within MG-1 that is of particular interest is a highly repetitive, evolutionarily conserved sequence (EC-1) originally described by Miesfeld et al. (24). Its nucleotide sequence reveals a substantial stretch of the simple repeating dinucleotide d(TG AC),. Similar sequences of d(TG AC), (n = 17 in the MG-1 fragment) are found repeated approximately 50,000 times in the human genome and appear to be highly repetitive in all eucaryotic cell genomes examined by Southern blot analysis (13,24). Long tracts of the sequence d(TG AC)n have been observed by direct DNA sequencing in or near many eucaryotic genes (26,27,38,43,49), and it has been suggested that such sequences may be involved in the initiation of genetic exchanges (28,39,43 probe in yeast are not due to strictly alternating T and G (or A and C) residues, but consist of tandem irregular repeats of the general form C1_3A and have been localized to the telomeres of yeast chromosomes (37,60,61). The C1_3A tracts present at yeast telomeres that hybridize with d(TG AC), probes are on the order of one to several hundred base pairs in length (37, 60). However, it is predicted that there are 15 to 20 d(TG AC),,-hybridizing sequences that are not telomeric or telomere associated (60).An analysis of the MG-1 fragment in yeast showed that it was very active in meiotic recombination even in the absence of the d(TG AC)17 sequence (58). However, in this experiment two small d(TG AC), runs of 10 and 14 base pairs (bp) (n = 5 and 7, respectively) remained in the tested fragment. We were therefore interested in determining whether d(TG AC), sequences are frequently associated with meiotic exchanges when separated from other, unique ,B-globin sequences. Using our in vivo assay for meiotic recombination, we show here that the addition of cloned fragments of d(TG. AC)40, d(TG AC)60, and d(TG AC)75 (80, 120, and 150 bp, respectively) to a 620-bp interval between two yeast genes enhances reciprocal recombination and increases the genetic distance between the two genes by a factor of seven. In addition, the presence of d(TG. AC),, when homozygous or heterozygous, generated ...

show abstract

“…[6] The B-Z transition has been observed in alternating purine-pyrimidine sequences, such as poly(dG-dC) Á poly(dG-dC). [7][8][9] Z-DNA is stabilized under high ionic strength conditions (over 4 M NaCl or 0.7 M MgCl 2 ), [10,11] or in the presence of organic solvents, [12,13] hexaamminecobalt (III) ([Co(NH 3 ) 6 ] 3þ ), [14] or spermine. [11] Methylation at the 5-position of the cytosine base greatly facilitates the Z-type formation.…”

Section: Introductionmentioning

confidence: 99%

B–Z DNA Transition Triggered by a Cationic Comb‐Type Copolymer

Shimada

Kano

Maruyama

2009

Adv Funct Materials

View full text Add to dashboard Cite

The conformational transition from right‐handed B–DNA to left‐handed Z–DNA—the B–Z transition—has received increased attention recently because of its potential roles in biological systems and its applicability to bionanotechnology. Though the B–Z transition of poly(dG–dC) · poly(dG–dC) is inducible under high salt concentration conditions (over 4 M NaCl) or by addition of multivalent cations, such as hexaamminecobalt(III), no cationic polymer were known to induce the transition. In this study, it is shown by circular dichroism and UV spectroscopy that the cationic comb‐type copolymer, poly(L‐lysine)‐graft‐dextran, but not poly(L‐lysine) homopolymer or a basic peptide, induces the B–Z transition of poly(dG–dC) · poly(dG–dC). At a cationic amino group concentration of 10−4 M the copolymer stabilizes Z–DNA. The transition pathway from the B to the Z form is different to that observed previously. We speculate that the cationic backbone of the copolymer, which reduces electrostatic repulsion among DNA phosphate groups, and the hydrophilic dextran chains, which reduce activity of water, cooperate to induce the B–Z transition. The copolymer specifically modified the micro‐environment around DNA molecules to induce Z–DNA formation through stable and spontaneous inter‐polyelectrolyte complex formation.

show abstract

Conformational transitions of poly(dA-dT).poly(dA-dT) in ethanolic solutions

Cited by 59 publications

References 28 publications

Conformational Isomerizations of the Poly(dA-dT) and Poly(amino²dA-dT) Duplexes Involving the Unusual X-DNA Double Helix: A Fourth Derivative Spectrophotometric Study

Conformational Isomerizations of the Poly(dA-dT) and Poly(amino²dA-dT) Duplexes Involving the Unusual X-DNA Double Helix: A Fourth Derivative Spectrophotometric Study

The evolutionarily conserved repetitive sequence d(TG.AC)n promotes reciprocal exchange and generates unusual recombinant tetrads during yeast meiosis.

B–Z DNA Transition Triggered by a Cationic Comb‐Type Copolymer

Contact Info

Product

Resources

About

Conformational transitions of poly(dA-dT).poly(dA-dT) in ethanolic solutions

Cited by 59 publications

References 28 publications

Conformational Isomerizations of the Poly(dA-dT) and Poly(amino2dA-dT) Duplexes Involving the Unusual X-DNA Double Helix: A Fourth Derivative Spectrophotometric Study

Conformational Isomerizations of the Poly(dA-dT) and Poly(amino2dA-dT) Duplexes Involving the Unusual X-DNA Double Helix: A Fourth Derivative Spectrophotometric Study

The evolutionarily conserved repetitive sequence d(TG.AC)n promotes reciprocal exchange and generates unusual recombinant tetrads during yeast meiosis.

B–Z DNA Transition Triggered by a Cationic Comb‐Type Copolymer

Contact Info

Product

Resources

About

Conformational Isomerizations of the Poly(dA-dT) and Poly(amino²dA-dT) Duplexes Involving the Unusual X-DNA Double Helix: A Fourth Derivative Spectrophotometric Study

Conformational Isomerizations of the Poly(dA-dT) and Poly(amino²dA-dT) Duplexes Involving the Unusual X-DNA Double Helix: A Fourth Derivative Spectrophotometric Study