Our work focuses on the structure, mechanism of promoter recognition and activation of two phage N4-coded RNA polymerases, vRNAP and N4 RNAPII, which belong to the T7 RNAP-like family. The 3,500 amino acid vRNAP recognizes a hairpin and specific sequences at its promoters. Promoter activation requires supercoiling and EcoSSB. We defined and characterized an active central domain (1,106 mini-vRNAP, the most distantly related member of the family) and have recently determined its crystal structure at 2.0 A resolution. We will define the in vivo structure of vRNAP promoters to support our model of supercoiled-induced hairpin extrusion, identify determinants of promoter recognition using biochemical and genetic approaches, determine the structure of the mini-vRNAP-promoter DNA complex by X-ray crystallography, define a nucleic acid scaffold for crystallization of the elongation complex, and define amino acid residues responsible for the EcoSSB-vRNAP interaction that elicits EcoSSB-assisted product displacement. N4 RNAPII is a heterodimer that does not recognize promoter sequences. In vivo it requires N4gp2, a ssDNA binding protein that recruits N4 RNAPII to ssDNA specifically. Middle promoters contain two sets of conserved sequences separated by 12-25 bp. We will identify all N4 RNAPII promoters and analyze their in vivo structure to test our model of promoter recognition, determine the crystal structure of N4 RNAPII and of its complex with gp2, characterize gp2 by determining its native MW, defining determinants of ssDNA-binding and of interaction with RNAPII, and the target of gp2 interaction in RNAPII. We will identify the N4-coded protein responsible for N4 RNAPII promoter specificity, and characterize its interaction with DNA, RNAPII and/or gp2 to reconstitute a system with purified components. We expect to provide new insights into strategies of promoter-RNAP interaction, into structure of factor-dependent T7-1ike RNA polymerases, and into the role of DNA structural transitions and single-stranded DNA binding proteins in transcription regulation.

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Research Project (R01)
Project #
5R01AI012575-33
Application #
7456582
Study Section
Special Emphasis Panel (ZRG1-MBC-2 (01))
Program Officer
Korpela, Jukka K
Project Start
2004-07-01
Project End
2009-06-30
Budget Start
2008-07-01
Budget End
2009-06-30
Support Year
33
Fiscal Year
2008
Total Cost
$498,762
Indirect Cost
Name
University of Chicago
Department
Genetics
Type
Schools of Medicine
DUNS #
005421136
City
Chicago
State
IL
Country
United States
Zip Code
60637
Lenneman, Bryan R; Rothman-Denes, Lucia B (2015) Structural and biochemical investigation of bacteriophage N4-encoded RNA polymerases. Biomolecules 5:647-67
Molodtsov, Vadim; Nawarathne, Irosha N; Scharf, Nathan T et al. (2013) X-ray crystal structures of the Escherichia coli RNA polymerase in complex with benzoxazinorifamycins. J Med Chem 56:4758-63
Basu, Ritwika S; Murakami, Katsuhiko S (2013) Watching the bacteriophage N4 RNA polymerase transcription by time-dependent soak-trigger-freeze X-ray crystallography. J Biol Chem 288:3305-11
Chen, Yuanyuan; Basu, Ritwika; Gleghorn, Michael L et al. (2011) Time-resolved events on the reaction pathway of transcript initiation by a single-subunit RNA polymerase: Raman crystallographic evidence. J Am Chem Soc 133:12544-55
Gleghorn, Michael L; Davydova, Elena K; Basu, Ritwika et al. (2011) X-ray crystal structures elucidate the nucleotidyl transfer reaction of transcript initiation using two nucleotides. Proc Natl Acad Sci U S A 108:3566-71
Yano, Sho T; Rothman-Denes, Lucia B (2011) A phage-encoded inhibitor of Escherichia coli DNA replication targets the DNA polymerase clamp loader. Mol Microbiol 79:1325-38
McPartland, Jennifer; Rothman-Denes, Lucia B (2009) The tail sheath of bacteriophage N4 interacts with the Escherichia coli receptor. J Bacteriol 191:525-32
Davydova, Elena K; Kaganman, Irene; Kazmierczak, Krystyna M et al. (2009) Identification of bacteriophage N4 virion RNA polymerase-nucleic acid interactions in transcription complexes. J Biol Chem 284:1962-70
Gleghorn, Michael L; Davydova, Elena K; Rothman-Denes, Lucia B et al. (2008) Structural basis for DNA-hairpin promoter recognition by the bacteriophage N4 virion RNA polymerase. Mol Cell 32:707-17
Murakami, Katsuhiko S; Davydova, Elena K; Rothman-Denes, Lucia B (2008) X-ray crystal structure of the polymerase domain of the bacteriophage N4 virion RNA polymerase. Proc Natl Acad Sci U S A 105:5046-51

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