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A new model for DNA containing A.T and I.C base pairs.
Author(s) -
Drew H.R.,
Dickerson R.E.
Publication year - 1982
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.1460-2075.1982.tb01227.x
Subject(s) - antiparallel (mathematics) , base pair , biology , pairing , dna , helix (gastropod) , diffraction , physics , crystallography , genetics , optics , condensed matter physics , ecology , chemistry , superconductivity , quantum mechanics , snail , magnetic field
DNA polymers containing exclusively A.T or I.C base pairs frequently exhibit D‐ or E‐type X‐ray diffraction patterns when dried. The distribution of intensities in fiber patterns appears to demand helical structures with 7 and 7.5 bp/turn, respectively, but it is not stereochemically possible to wind a right‐handed antiparallel B‐family helix this tightly. It is a simple matter, however, to build a left‐handed helix with 7‐7.5 bp/turn by incorporating Hoogsteen pairing into a Z helix framework. X‐ray intensities calculated from this novel left‐handed Hoogsteen model provide as reasonable a fit to the D‐DNA diffraction pattern as do intensities calculated from previously proposed right‐handed 8‐fold models.