Cooperative nonenzymic base recognition. Kinetics of the binding of a base monomer to a complementary polynucleotide template

✍ Scribed by Geoffrey W. Hoffman; Dietmar Pörschke

• Publisher: Wiley (John Wiley & Sons)
• Year: 1973
• Tongue: English
• Weight: 728 KB
• Volume: 12
• Category: Article
• ISSN: 0006-3525
• DOI: 10.1002/bip.1973.360120714

✦ Synopsis

Abstract

The kinetics of double‐helix formation by poly U and the complementary monomer N‐6,9‐dimethyladenine (m^6^m^9^A) has been measured using a new fast temperature‐jump apparatus. The cooperative binding kinetics are complicated by the extensive self‐association of the monomers, but a satisfactory analysis using average relaxation times was possible in terms of three different models. Application of a model which considers only monomer binding yields the upper limit for the binding rate constant of an m^6^m^9^A monomer next to an already bound monomer on a poly U strand: (2 ± 0.4) × 10^8^ M^−1^sec^−1^. A lower limit is found by using a model which allows for binding of all m^6^m^9^A stacks to poly U with equal rate constants: (3 ± 0.3) × 10^7^ M^−1^sec^−1^. A third model with “weighted” rate constants consistent with the data: (7.5 ± 1.0) × 10^7^ M^−1^sec^−1^. The rate of cooperative binding of m^6^m^9^A to the trimer UpUpU has also been measured. The rate constants obtained with the trimer agree with those obtained with the polymer for each of the three models within experimental error.