Poly(dA-dT). poly(dA-dT) two-pathway proton exchange mechanism. Effect of general and specific base catalysis on deuteration rates
The deuteration rates of the poly(dA-dT).poly(dA-dT) amino and imino protons have been measured with stopped-flow spectrophotometry as a function of general and specific base catalyst concentration. Two proton exchange classes are found with time constants differing by a factor of 10 (4 and 0.4 s-1). The slower class represents the exchange of the adenine amino protons whereas the proton of the faster class has been assigned to the thymine imino proton. The exchange rates of these two classes of protons are independent of general and specific base catalyst concentration. This very characteristic behavior demonstrates that in our experimental conditions the exchange rates of the imino and amino protons in poly(dA-dT).poly(dA-dT) are limited by two different conformational fluctuations. We present a three-state exchange mechanism accounting for our experimental results.
- Research Organization:
- Centre de Biophysique Moleculaire, Orleans, France
- OSTI ID:
- 5127466
- Journal Information:
- Biochemistry; (United States), Journal Name: Biochemistry; (United States) Vol. 11; ISSN BICHA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
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59 BASIC BIOLOGICAL SCIENCES
AMINES
AZINES
BARYONS
CHEMICAL REACTIONS
DEUTERATION
DEUTERIUM COMPOUNDS
ELEMENTARY PARTICLES
FERMIONS
HADRONS
HETEROCYCLIC COMPOUNDS
HYDROGEN COMPOUNDS
HYDROXY COMPOUNDS
ISOTOPIC EXCHANGE
MATHEMATICS
NUCLEONS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
OXYGEN COMPOUNDS
PROTONS
PYRIMIDINES
THYMINE
URACILS
WATER