'''MOLECULAR STRUCTURE OF D(CGC[E6G]AATTCGCG) COMPLEXED WITH HOECHST 33342'''
===MOLECULAR STRUCTURE OF D(CGC[E6G]AATTCGCG) COMPLEXED WITH HOECHST 33342===
==Overview==
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O6-ethyl-G (e6G) is an important DNA lesion, caused by the exposure of cells to alkylating agents such as N-ethyl-N-nitrosourea. A strong correlation exists between persistence of e6G lesion and subsequent carcinogenic conversion. We have determined the three-dimensional structure of a DNA molecule incorporating the e6G lesion by X-ray crystallography. The DNA dodecamer d(CGC[e6G]AATTCGCG), complexed to minor groove binding drugs Hoechst 33258 or Hoechst 33342, has been crystallized in the space group P212121, isomorphous to other related dodecamer DNA crystals. In addition, the native dodecamer d(CGCGAATTCGCG) was crystallized with Hoechst 33342. All three new structures were solved by the molecular replacement method and refined by the constrained least squares procedure to R-factors of approximately 16% at approximately 2.0 A resolution. In the structure of three Hoechst drug-dodecamer complexes in addition to the one published earlier [Teng et al. (1988) Nucleic Acids Res., 16, 2671-2690], the Hoechst molecule lies squarely at the central AATT site with the ends approaching the G4-C21 and the G16-C9 base pairs, consistent with other spectroscopic data, but not with another crystal structure reported [Pjura et al. (1987) J. Mol. Biol., 197, 257-271]. The two independent e6G-C base pairs in the DNA duplex adopt different base pairing schemes. The e6G4-C21 base pair has a configuration similar to a normal Watson-Crick base pair, except with bifurcated hydrogen bonds between e6G4 and C21, and the ethyl group is in the proximal orientation. In contrast, the e6G16-C9 base pair adopts a wobble configuration and the ethyl group is in the distal orientation.(ABSTRACT TRUNCATED AT 250 WORDS)
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==About this Structure==
==About this Structure==
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[[Category: Double helix]]
[[Category: Double helix]]
[[Category: Modified]]
[[Category: Modified]]
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''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Mon Jun 30 15:27:11 2008''
Revision as of 15:27, 30 June 2008
This article has been automatically seeded. Changes to this page should pertain to the PDB entry only and not to the protein or biomolecule in general.
Full crystallographic information is available from OCA.
ReferenceReference
Conformation of B-DNA containing O6-ethyl-G-C base pairs stabilized by minor groove binding drugs: molecular structure of d(CGC[e6G]AATTCGCG complexed with Hoechst 33258 or Hoechst 33342., Sriram M, van der Marel GA, Roelen HL, van Boom JH, Wang AH, EMBO J. 1992 Jan;11(1):225-32. PMID:1371249
