124d
From Proteopedia
OCA (Talk | contribs)
(New page: 200px<br /><applet load="124d" size="450" color="white" frame="true" align="right" spinBox="true" caption="124d" /> '''STRUCTURE OF A DNA:RNA HYBRID DUPLEX: WHY RN...)
Next diff →
Revision as of 19:41, 24 November 2007
|
STRUCTURE OF A DNA:RNA HYBRID DUPLEX: WHY RNASE H DOES NOT CLEAVE PURE RNA
Overview
The solution structure of the DNA:RNA hybrid duplex, d(GTCACATG):r(caugugac) has been determined by means of two-dimensional, nuclear Overhauser effect (2D-NOE) spectra, restrained molecular dynamics, and full-relaxation matrix stimulation of the 2D-NOE spectra. The DNA:RNA, hybrid duplex assumes neither an A-form nor a B-form structure in, solution, but an intermediate heteromerous duplex structure. The sugars of, the RNA strand have a normal N-type C3'-endo conformation, but the DNA, strand sugars have neither N-type nor S-type conformations; instead, they, have an unexpected intermediate O4'-endo conformation. The negative, x-displacement, as well as the small rise and positive inclination of the, base-pairs, resembles A-form morphology but the minor groove width is, intermediate between that of A-form and B-form duplexes. Both the DNA and, RNA strands show prominent sequence-dependent variations in their helical, parameters. Combined analysis of NOE and J-coupling data indicates that, the DNA sugars are not in a dynamical two-state equilibrium. The detailed, three-dimensional structure of this DNA:RNA hybrid molecule leads to a, proposed model for its interaction with RNase H. Several specific, structural features of the enzyme complexed with the hybrid duplex appear, to explain the mechanism whereby RNase H discriminates between DNA:RNA, hybrid duplexes and pure RNA:RNA duplexes.
About this Structure
124D is a Protein complex structure of sequences from [1]. Full crystallographic information is available from OCA.
Reference
Structure of a DNA:RNA hybrid duplex. Why RNase H does not cleave pure RNA., Fedoroff OYu, Salazar M, Reid BR, J Mol Biol. 1993 Oct 5;233(3):509-23. PMID:8411159
Page seeded by OCA on Sat Nov 24 21:49:16 2007
