Synthesis of Poly[d(A‐s4T) · d(A‐s4T)] by Bacillus subtilis DNA Polymerase

Lezius, Axel G.; Rath, Ute

doi:10.1111/j.1432-1033.1971.tb19667.x

Cited by 10 publications

(7 citation statements)

References 10 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…As stated previously [8] conformation I, which is present in neutral buffers of low-ionic strength, exhibits a large hypochromic effect at 335nm if compared with the polymer in the random-coil state or after digestion with nucleases. The rather broad long-wave absorption envelope of 4-thiothymidine in the orderedpolymer structure shows a bathochromic shift of the maximum by 14nm and as a consequence a hyperchromic effect above 360 nm with respect to the monomer.…”

Section: Spectral Characterisationmentioning

confidence: 92%

See 1 more Smart Citation

A Synthetic DNA with Unusual Base‐Pairing

Gottschalk

Kopp

Lezius

1971

European Journal of Biochemistry

Self Cite

View full text Add to dashboard Cite

The alternating polydeoxynucleotide poly[d(A-s4T) -d(A-s4T)] with 4-thiothymidine substituting for thymidine shows anomalous spectral and hydrodynamic properties which are inconsistent with a Watson-Crick structure but agree with a model of a left-handed double helix built up from Haschemeyer-Sobell (reversed Hoogsteen) base-pairs instead.Optical-rotatory-dispersion and circular-dichroism spectra exhibit a strong negative Cotton effect centered near 400 nm that is assigned to a n + n* transition of the thioamide chromophor and that is a t least unexpected if the sulfur atom participates in the hydrogen bridge. From the inversion of the Cotton effects between 370 and 400 nm with respect to the monomer or randomcoil state it is inferred that 4-thiothymidine attains the unusual syn conformation in the ordered polymer. At pH below 4.5 the polymer is protonated at N-1 of the deoxyadenosine residues and changes into a different helical conformation. As the inflection point of the proton-induced transition falls close to the basic p K of deoxyadenosine monophosphate, also N-1 (A) is probably not involved in hydrogen bonding. Therefore, only N-7 (A) and 0 -2 (s4T) remain as proton acceptors for base-pairing. The polymer undergoes cooperative temperature-dependent transitions in concentrated solutions of 1 : 1 electrolytes. Two more helical conformations are characterized by ultraviolet, optical-rotatory dispersion, and circular dichroism. I n addition, changes in hydrodynamic parameters, e.g. sedimentation coefficient, buoyant density and partial specific-volume are reported. A structural hysteresis is observed in a helix-helix transition and is discussed in terms of metastable states indicated from a phase diagram. Definition. A,, unit, the quantity of material contained in 1 ml of a solution which has an absorbance of 1 a t 345 nm, when measured in a 1-cm pathlength cell.can become less important relative to other factors under conditions of reduced solvent-solvent interactions which are met in solutions deviating from neutrality, in mixtures of water and organic solvents, and in concentrated salt solutions. These as well as chemical modification of the nucleosides may lead to some interference with the Watson-Crick structure and eventually favor even an alternative basepairing.I n this study the anomalous behaviour of a synthetic DNA is described which is distinctly different in structure from the usual Watson-Crick structure. The alternating polydeoxynucleotide poly[d(A-s*T) d(As4T)], prepared first enzymatically in this laboratory [7, 81, contains the analog nucleoside 4-thiothymidine instead of thymidine. Since in the Watson-Crick structure the 4-0x0 group of thymidine is involved in basepairing, substitution of this oxygen by sulfur should cause a t least some perturbation of the hydrogen bond. Therefore, the question of structure and stability of this biopolymer has intrigued us from the very beginning. As reported briefly [9], two interconvertible conformations differing in buoyant density were detected during...

show abstract

Section: Spectral Characterisationmentioning

confidence: 92%

“…Poly[d(A-s4T) * d(A-s4T)] was prepared by extensive synthesis with Bacillus subtilis DNA-polymerase from dATP and s4dTTP as described in the preceding publication [8]. Reagent-grade chemicals were used if commercially available ; solutions were made with double-distilled water from a quartz apparatus.…”

Section: Methodsmentioning

confidence: 99%

A Synthetic DNA with Unusual Base‐Pairing

Gottschalk

Kopp

Lezius

1971

European Journal of Biochemistry

Self Cite

View full text Add to dashboard Cite

show abstract

“…A, before, and B, after degradation to mononuc eotides. b) at 335 nm: zero for the normal nucleotides and 21000 for s Td (19). The values for the base composition of fd RF DNA were derived from the known sequence of the plus-strand: 34.5% Ad, 24.6% Td, 20.7% Cd, 20.2% Gd.…”

Section: Resultsmentioning

confidence: 99%

“…These effects did not correlate with the s Td-content of the fragments, but obviously were sequence specific. DISCUSSION 4 Several years ago s T TP had first been synthesized and d tested as substrate for DNA polymerases (18)(19)(20). It was found that templates of strictly alternating sequences like poly(Ad-Td) and poly(Ad.Cd) were able to direct incorporation of s T into the complementary strand.…”

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Enzymatic synthesis, ligation, and restriction of DNA containing deoxy-4-thiothymidine

Höfer

Köster

1981

Nucl Acids Res

View full text Add to dashboard Cite

Phage fd RF I DNA1 about 90% substituted by deoxy-4-thiothymidine (s4Td) in the codogenic strand was synthesized by the simultaneous actions of DNA polymerase I and DNA ligase. While the rate of DNA synthesis was considerably reduced, the yield the rate of DNA synthesis was considerably reduced, the yield was not affected in the presence of s4TdTP. The conversion of RF II to RF I DNA by DNA ligase was even improved. This effect seems to be related with an altered ratio of affinity of polymerase and ligase for the s4Td-containing substrate. The presence of the base analogue in the DNA was verified independently by chromatographic and spectroscopic methods. The modified genome could be cleaved by restriction endonucleases Hpa II (C/CGG)d and Taq I (T/CGA)d. A number of the fragments produced showed altered mobilities under the conditions of polyacrylamide gel electrophoresis.

show abstract

Über die dynamische Struktur einer synthetischen Desoxyribonucleinsäure

Lezius

1972

Angewandte Chemie

View full text Add to dashboard Cite

Synthesis of Poly[d(A‐s⁴T) · d(A‐s⁴T)] by Bacillus subtilis DNA Polymerase

Cited by 10 publications

References 10 publications

A Synthetic DNA with Unusual Base‐Pairing

A Synthetic DNA with Unusual Base‐Pairing

Enzymatic synthesis, ligation, and restriction of DNA containing deoxy-4-thiothymidine

Über die dynamische Struktur einer synthetischen Desoxyribonucleinsäure

Contact Info

Product

Resources

About