Comparison of binding of mixed ribose-deoxyribose analogues of CUCU to a ribozyme and to GGAGAA by equilibrium dialysis: evidence for ribozyme specific interactions with 2' OH groups.
Dissociation constants at 15 degrees C were measured by equilibrium dialysis for the binding of rCrUrCrU, dCrUrCrU, rCdUrCrU, rCrUdCrU, and rCrUrCdU to the L-21 ScaI form of the self-splicing group I LSU intron from Tetrahymena thermophila. Substitution of deoxyribose for ribose in each of the middle two positions makes the free energy change for binding 1-2 kcal/mol less favorable, compared to about 0.3 kcal/mol less favorable for each of the terminal positions. Dissociation constants for binding of the same oligomers to rGGAGAA were measured by optical melting methods. Substitution of a single deoxyribose for ribose makes the free energy change for binding less favorable by 0.4-0.9 kcal/mol for this simple duplex formation. Comparison of the effects for binding to ribozyme and to rGGAGAA indicate that ribozyme-specific tertiary interactions dependent on the middle two 2' OH groups of rCrUrCrU add about 2 kcal/mol of favorable free energy for binding to L-21 ScaI. Comparisons are made with results from gel retardation studies [Pyle, A. M., McSwiggen, J. A., & Cech, T. R. (1990) Proc. Natl. Acad. Sci. U.S.A. 87, 8187-8191; Pyle, A. M., & Cech, T. R. (1991) Nature (London) 350, 628-631].
Department of Chemistry, University of Rochester, New York 14627-0216.
P C
PC
Bevilacqua
D H
DH
Turner
D000818:Animals; D001483:Base Sequence; D015252:Deoxyribonucleases, Type II Site-Specific / Q000378:metabolism; D003956:Dialysis; D007438:Introns; D008969:Molecular Sequence Data; D009838:Oligodeoxyribonucleotides / Q000378:metabolism*; D009843:Oligoribonucleotides / Q000378:metabolism*; D016337:RNA, Catalytic / Q000378:metabolism*; D016808:Tetrahymena thermophila / Q000235:genetics; D013816:Thermodynamics
D009838:Oligodeoxyribonucleotides; D009843:Oligoribonucleotides; D016337:RNA, Catalytic; C047020:endodeoxyribonuclease ScaI; D015252:Deoxyribonucleases, Type II Site-Specific