Crystallographic analysis of an RNA polymerase σ-subunit fragment complexed with -10 promoter element ssDNA: quadruplex formation as a possible tool for engineering crystal contacts in protein-ssDNA complexes.
Publication Type:
Journal ArticleSource:
Acta Crystallogr Sect F Struct Biol Cryst Commun, Volume 69, Issue Pt 9, p.950-5 (2013)Keywords:
Crystallography, X-Ray, DNA, Single-Stranded, DNA-Directed RNA Polymerases, G-Quadruplexes, Genetic Engineering, Models, Molecular, Promoter Regions, Genetic, Protein Structure, Tertiary, Recombinant Proteins, Sigma Factor, ThermusAbstract:
<p>Structural studies of -10 promoter element recognition by domain 2 of the RNA polymerase σ subunit [Feklistov & Darst (2011), Cell, 147, 1257-1269] reveal an unusual crystal-packing arrangement dominated by G-quartets. The 3'-terminal GGG motif of the oligonucleotide used in crystallization participates in G-quadruplex formation with GGG motifs from symmetry-related complexes. Stacking between neighboring G-quadruplexes results in the formation of pseudo-continuous four-stranded columns running throughout the length of the crystal (G-columns). Here, a new crystal form is presented with a different arrangement of G-columns and it is proposed that the fortuitous finding of G-quartet packing could be useful in engineering crystal contacts in protein-ssDNA complexes. </p>