Open AccessCrystallographic 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
Author(s) -
Feklistov Andrey,
Darst Seth A.
Publication year - 2013
Publication title -
acta crystallographica section f
Language(s) - English
Resource type - Journals
ISSN - 1744-3091
DOI - 10.1107/s1744309113020368
Subject(s) - stacking , crystallography , oligonucleotide , protein subunit , chemistry , crystallization , dna , polymerase , crystal (programming language) , g quadruplex , rna polymerase , rna , stereochemistry , biophysics , biology , gene , biochemistry , organic chemistry , computer science , programming language
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.