Tags

Type your tag names separated by a space and hit enter

Influence of primary structure on initial free radical products trapped in A:T polydeoxynucleotides X-irradiated at 4 K.
Radiat Res. 1993 Feb; 133(2):143-50.RR

Abstract

EPR measurements were made at Q-band microwave frequencies on powder samples pressed into pellets and X-irradiated at 4 K. Measurements were made at 4 K after no anneal, then after a 77 K anneal, and then after a 300 K anneal. In poly(dA):poly(T) the free radical distribution is approximately a simple sum of the distributions in the separate homopolymers. In poly(dA-T) the free radical distribution differs from that of poly(dA):poly(T). The clearest difference is that in poly-(dA):poly(T) the concentration of one-electron-reduced thymine (Tre.) is reduced relative to the total radical concentration. On warming the thymine-containing samples from 77 K to room temperature, the Tox. radical disappears and the (T-H5'). radical appears. Also, the Tre. radical disappears and the (T + H6). radical appears. There are three main conclusions. First, little or no transfer of free radicals between strands is needed to explain the data. Second, when A and T are interstacked, either the Tre. radical is less stable against recombination than other radical products or radical transfer occurs to an adjacent adenine. Third, in the poly- and oligonucleotides, the Tox. radical is a likely precursor to the (T-H5'). radical.

Authors+Show Affiliations

Department of Physics & Electronics Engineering, University of Scranton, Pennsylvania 18510.No affiliation info available

Pub Type(s)

Journal Article
Research Support, U.S. Gov't, P.H.S.

Language

eng

PubMed ID

8382367

Citation

Spalletta, R A., and W A. Bernhard. "Influence of Primary Structure On Initial Free Radical Products Trapped in A:T Polydeoxynucleotides X-irradiated at 4 K." Radiation Research, vol. 133, no. 2, 1993, pp. 143-50.
Spalletta RA, Bernhard WA. Influence of primary structure on initial free radical products trapped in A:T polydeoxynucleotides X-irradiated at 4 K. Radiat Res. 1993;133(2):143-50.
Spalletta, R. A., & Bernhard, W. A. (1993). Influence of primary structure on initial free radical products trapped in A:T polydeoxynucleotides X-irradiated at 4 K. Radiation Research, 133(2), 143-50.
Spalletta RA, Bernhard WA. Influence of Primary Structure On Initial Free Radical Products Trapped in A:T Polydeoxynucleotides X-irradiated at 4 K. Radiat Res. 1993;133(2):143-50. PubMed PMID: 8382367.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Influence of primary structure on initial free radical products trapped in A:T polydeoxynucleotides X-irradiated at 4 K. AU - Spalletta,R A, AU - Bernhard,W A, PY - 1993/2/1/pubmed PY - 1993/2/1/medline PY - 1993/2/1/entrez SP - 143 EP - 50 JF - Radiation research JO - Radiat. Res. VL - 133 IS - 2 N2 - EPR measurements were made at Q-band microwave frequencies on powder samples pressed into pellets and X-irradiated at 4 K. Measurements were made at 4 K after no anneal, then after a 77 K anneal, and then after a 300 K anneal. In poly(dA):poly(T) the free radical distribution is approximately a simple sum of the distributions in the separate homopolymers. In poly(dA-T) the free radical distribution differs from that of poly(dA):poly(T). The clearest difference is that in poly-(dA):poly(T) the concentration of one-electron-reduced thymine (Tre.) is reduced relative to the total radical concentration. On warming the thymine-containing samples from 77 K to room temperature, the Tox. radical disappears and the (T-H5'). radical appears. Also, the Tre. radical disappears and the (T + H6). radical appears. There are three main conclusions. First, little or no transfer of free radicals between strands is needed to explain the data. Second, when A and T are interstacked, either the Tre. radical is less stable against recombination than other radical products or radical transfer occurs to an adjacent adenine. Third, in the poly- and oligonucleotides, the Tox. radical is a likely precursor to the (T-H5'). radical. SN - 0033-7587 UR - https://www.unboundmedicine.com/medline/citation/8382367/Influence_of_primary_structure_on_initial_free_radical_products_trapped_in_A:T_polydeoxynucleotides_X_irradiated_at_4_K_ DB - PRIME DP - Unbound Medicine ER -