127d
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(New page: 200px<br /><applet load="127d" size="450" color="white" frame="true" align="right" spinBox="true" caption="127d, resolution 2.000Å" /> '''DNA (5'-D(*CP*GP*CP...)
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DNA (5'-D(*CP*GP*CP*GP*AP*AP*TP*TP*CP*GP*CP*G)-3') COMPLEXED WITH HOECHST 33258
Overview
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)
About this Structure
127D is a Protein complex structure of sequences from [1] with HT as ligand. Full crystallographic information is available from OCA.
Reference
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
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