1egk
From Proteopedia
CRYSTAL STRUCTURE OF A NUCLEIC ACID FOUR-WAY JUNCTION
Overview
A crystal structure of a 108 nucleotide RNA-DNA complex containing a four-way junction was solved at 3.1 A resolution. The structure of the junction differs substantially from the "stacked-X" conformation observed previously, due to a 135 degrees rotation of the branches. Comparison of the two conformers provides insight into the factors contributing to the flexibility of four-way junctions. The stacked-X conformation maximizes base-stacking but causes unfavorable repulsion between phosphate groups, whereas the 135 degrees -rotated "crossed" conformation minimizes electrostatic clashes at the expense of reduced base-stacking. Despite the large rotation of the branches, both junction structures exhibit an antiparallel arrangement of the continuous strands and opposite polarity of the crossover strands.
About this Structure
Full crystallographic information is available from OCA.
Reference
Alternative conformations of a nucleic acid four-way junction., Nowakowski J, Shim PJ, Stout CD, Joyce GF, J Mol Biol. 2000 Jun 30;300(1):93-102. PMID:10864501 Page seeded by OCA on Fri May 2 15:04:33 2008
