TY - JOUR
T1 - Structural Basis for DNA-Hairpin Promoter Recognition by the Bacteriophage N4 Virion RNA Polymerase
AU - Gleghorn, Michael L.
AU - Davydova, Elena K.
AU - Rothman-Denes, Lucia B.
AU - Murakami, Katsuhiko S.
N1 - Funding Information:
We thank E. Davydova for technical assistance and the staff at X25 of the National Synchrotron Light Source and H. Yennawar for support. We thank E.P. Geiduschek and J.W. Roberts for critiques of the manuscript. We thank Hauptman-Woodward Institute for screening crystallization conditions. Figures were prepared using PyMOL. This work was supported by NIH grants AI12575 to L.B.R.-D. and GM071897 to K.S.M.
PY - 2008/12/5
Y1 - 2008/12/5
N2 - Coliphage N4 virion-encapsidated RNA polymerase (vRNAP) is a member of the phage T7-like single-subunit RNA polymerase (RNAP) family. Its central domain (mini-vRNAP) contains all RNAP functions of the full-length vRNAP, which recognizes a 5 to 7 base pair stem and 3 nucleotide loop hairpin DNA promoter. Here, we report the X-ray crystal structures of mini-vRNAP bound to promoters. Mini-vRNAP uses four structural motifs to recognize DNA sequences at the hairpin loop and stem and to unwind DNA. Despite their low sequence similarity, three out of four motifs are shared with T7 RNAP that recognizes a double-stranded DNA promoter. The binary complex structure and results of engineered disulfide linkage experiments reveal that the plug and motif B loop, which block the access of template DNA to the active site in the apo-form mini-vRNAP, undergo a large-scale conformational change upon promoter binding, explaining the restricted promoter specificity that is critical for N4 phage early transcription.
AB - Coliphage N4 virion-encapsidated RNA polymerase (vRNAP) is a member of the phage T7-like single-subunit RNA polymerase (RNAP) family. Its central domain (mini-vRNAP) contains all RNAP functions of the full-length vRNAP, which recognizes a 5 to 7 base pair stem and 3 nucleotide loop hairpin DNA promoter. Here, we report the X-ray crystal structures of mini-vRNAP bound to promoters. Mini-vRNAP uses four structural motifs to recognize DNA sequences at the hairpin loop and stem and to unwind DNA. Despite their low sequence similarity, three out of four motifs are shared with T7 RNAP that recognizes a double-stranded DNA promoter. The binary complex structure and results of engineered disulfide linkage experiments reveal that the plug and motif B loop, which block the access of template DNA to the active site in the apo-form mini-vRNAP, undergo a large-scale conformational change upon promoter binding, explaining the restricted promoter specificity that is critical for N4 phage early transcription.
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U2 - 10.1016/j.molcel.2008.11.010
DO - 10.1016/j.molcel.2008.11.010
M3 - Article
C2 - 19061645
AN - SCOPUS:56849089820
SN - 1097-2765
VL - 32
SP - 707
EP - 717
JO - Molecular cell
JF - Molecular cell
IS - 5
ER -