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Melting studies on spin‐labeled polyadenylic–polyuridylic complexes
Author(s) -
Pan YuChing E.,
Bobst Albert M.
Publication year - 1973
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.1973.360120213
Subject(s) - polynucleotide , chemistry , electron paramagnetic resonance , spin label , melting temperature , spin (aerodynamics) , crystallography , nucleotide , nuclear magnetic resonance , thermodynamics , biochemistry , materials science , physics , gene , composite material
Temperature‐dependent conformational transitions of spin‐labeled poly rA, spin‐labeled poly rU and the two‐stranded helical complexes consisting either of spin‐labeled rA·poly rU or spin‐labeled poly rU·poly rA have been measured by electron spin resonance spectrocopy. The polynucleotides were spin labeled with 4‐(2‐iodoacetamido)2,2,6,6‐tetramethylpiperidinooxyl and the spin label to nucleotide base ratio was approximately 1:600. The relationship between the log of tumbling time τ and the reciprocal absolute temperature for the spin‐labeled single and double‐stranded polynucleotides is presented. An agreement between T m OD (optical density melting) and T m sp (spin melting) is found for the complexes, which strongly supports the conclusion that the same temperature‐dependent structural changes are monitored with both techniques.