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Cleavage of a four‐way DNA junction by a restriction enzyme spanning the point of strand exchange.
Author(s) -
Murchie A. I.,
Portugal J.,
Lilley D. M.
Publication year - 1991
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1002/j.1460-2075.1991.tb08001.x
Subject(s) - stacking , cleavage (geology) , biology , restriction enzyme , dna , coaxial , enzyme , stereochemistry , biophysics , crystallography , genetics , physics , biochemistry , nuclear magnetic resonance , paleontology , fracture (geology) , chemistry , electrical engineering , engineering
The four‐way DNA junction is believed to fold in the presence of metal ions into an X‐shaped structure, in which there is pairwise coaxial stacking of helical arms. A restriction enzyme MboII has been used to probe this structure. A junction was constructed containing a recognition site for MboII in one helical arm, positioned such that stacking of arms would result in cleavage in a neighbouring arm. Strong cleavage was observed, at the sites expected on the basis of coaxial stacking. An additional cleavage was seen corresponding to the formation of an alternative stacking isomer, suggesting that the two isomeric forms are in dynamic equilibrium in solution.