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Temperature‐jump kinetics of the dC‐G‐T‐G‐A‐A‐T‐T‐C‐G‐C‐G double helix containing a G·T base pair and the dC‐G‐C‐A‐G‐A‐A‐T‐T‐C‐G‐C‐G double helix containing an extra adenine
Author(s) -
Chu Y. Gloria,
Tinoco Ignacio
Publication year - 1983
Publication title -
biopolymers
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.556
H-Index - 125
eISSN - 1097-0282
pISSN - 0006-3525
DOI - 10.1002/bip.360220415
Subject(s) - chemistry , kinetics , helix (gastropod) , activation energy , atmospheric temperature range , stereochemistry , crystallography , reaction rate constant , dissociation (chemistry) , kinetic energy , temperature jump , thermodynamics , physics , ecology , quantum mechanics , snail , biology
The kinetics of helix formation were investigated using the temperature‐jump technique for the following two molecules: dC‐G‐T‐G‐A‐A‐T‐T‐C‐G‐C‐G, which forms a double helix containing a G·T base pair(the G·T 12‐mer), and dC‐G‐C‐A‐G‐A‐A‐T‐T‐C‐G‐C‐G, which forms a double helix containing an extra adenine (the 13‐mer). When data were analyzed in an all‐or‐none model, the activation energy for the helix association process was 22 ± 4 kcal/mol for the G·T 12‐mer and 16 ± 7 kcal/mol for the 13‐mer. The activation energy for the helix‐dissociation process was 68 ± 2 kcal/mol for the G·T 12‐mer and 74 ± 3 kcal/mol for the 13‐mer. Rate constants for recombination were near 10 5 s −1 M −1 in the temperature range from 32 to 47°C; for the dissociation process, the rate constants varied from 1s −1 near 32°C to 130s −1 near 47°C. Possible effects of hairpin loops and fraying ends on the above data are discussed.