title: 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.
abstract: 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.
authors.affiliation: Laboratory of Molecular Biophysics, The Rockefeller University, 1230 York Avenue, New York, NY 10065, USA. afeklistov@rockefeller.edu
authors.forename: Andrey
authors.initials: A
authors.lastname: Feklistov
authors.forename: Seth A
authors.initials: SA
authors.lastname: Darst
mesh_terms: D018360:Crystallography, X-Ray; D004277:DNA, Single-Stranded / Q000737:chemistry*; D012321:DNA-Directed RNA Polymerases / Q000737:chemistry* / Q000235:genetics; D054856:G-Quadruplexes; D005818:Genetic Engineering; D008958:Models, Molecular; D011401:Promoter Regions, Genetic; D017434:Protein Structure, Tertiary; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics; D012808:Sigma Factor / Q000737:chemistry* / Q000235:genetics; D013824:Thermus / Q000737:chemistry* / Q000201:enzymology
chemical_list: D004277:DNA, Single-Stranded; D011994:Recombinant Proteins; D012808:Sigma Factor; D012321:DNA-Directed RNA Polymerases
keywords: -10 promoter element; G-quadruplex; RNA polymerase σ subunit; protein–ssDNA complexes