@article {805,
	title = {Structure of the SSB-DNA polymerase III interface and its role in DNA replication.},
	journal = {EMBO J},
	volume = {30},
	year = {2011},
	month = {2011 Oct 19},
	pages = {4236-47},
	abstract = {Interactions between single-stranded DNA-binding proteins (SSBs) and the DNA replication machinery are found in all organisms, but the roles of these contacts remain poorly defined. In Escherichia coli, SSB{\textquoteright}s association with the χ subunit of the DNA polymerase III holoenzyme has been proposed to confer stability to the replisome and to aid delivery of primers to the lagging-strand DNA polymerase. Here, the SSB-binding site on χ is identified crystallographically and biochemical and cellular studies delineate the consequences of destabilizing the χ/SSB interface. An essential role for the χ/SSB interaction in lagging-strand primer utilization is not supported. However, sequence changes in χ that block complex formation with SSB lead to salt-dependent uncoupling of leading- and lagging-strand DNA synthesis and to a surprising obstruction of the leading-strand DNA polymerase in vitro, pointing to roles for the χ/SSB complex in replisome establishment and maintenance. Destabilization of the χ/SSB complex in vivo produces cells with temperature-dependent cell cycle defects that appear to arise from replisome instability.},
	keywords = {Amino Acid Sequence, Bacterial Proteins, Base Sequence, DNA Polymerase III, DNA Replication, DNA, Single-Stranded, DNA-Binding Proteins, Escherichia coli, Escherichia coli Proteins, Holoenzymes, Molecular Sequence Data},
	issn = {1460-2075},
	doi = {10.1038/emboj.2011.305},
	author = {Marceau, Aimee H and Bahng, Soon and Massoni, Shawn C and George, Nicholas P and Sandler, Steven J and Marians, Kenneth J and Keck, James L}
}
@article {809,
	title = {Single molecule analysis of a red fluorescent RecA protein reveals a defect in nucleoprotein filament nucleation that relates to its reduced biological functions.},
	journal = {J Biol Chem},
	volume = {284},
	year = {2009},
	month = {2009 Jul 10},
	pages = {18664-73},
	abstract = {Fluorescent fusion proteins are exceedingly useful for monitoring protein localization in situ or visualizing protein behavior at the single molecule level. Unfortunately, some proteins are rendered inactive by the fusion. To circumvent this problem, we fused a hyperactive RecA protein (RecA803 protein) to monomeric red fluorescent protein (mRFP1) to produce a functional protein (RecA-RFP) that is suitable for in vivo and in vitro analysis. In vivo, the RecA-RFP partially restores UV resistance, conjugational recombination, and SOS induction to recA(-) cells. In vitro, the purified RecA-RFP protein forms a nucleoprotein filament whose k(cat) for single-stranded DNA-dependent ATPase activity is reduced approximately 3-fold relative to wild-type protein, and which is largely inhibited by single-stranded DNA-binding protein. However, RecA protein is also a dATPase; dATP supports RecA-RFP nucleoprotein filament formation in the presence of single-stranded DNA-binding protein. Furthermore, as for the wild-type protein, the activities of RecA-RFP are further enhanced by shifting the pH to 6.2. As a consequence, RecA-RFP is proficient for DNA strand exchange with dATP or at lower pH. Finally, using single molecule visualization, RecA-RFP was seen to assemble into a continuous filament on duplex DNA, and to extend the DNA approximately 1.7-fold. Consistent with its attenuated activities, RecA-RFP nucleates onto double-stranded DNA approximately 3-fold more slowly than the wild-type protein, but still requires approximately 3 monomers to form the rate-limited nucleus needed for filament assembly. Thus, RecA-RFP reveals that its attenuated biological functions correlate with a reduced frequency of nucleoprotein filament nucleation at the single molecule level.},
	keywords = {Cell Nucleus, DNA, DNA, Single-Stranded, Escherichia coli, Hydrogen-Ion Concentration, Kinetics, Luminescent Proteins, Nucleoproteins, Plasmids, Protein Binding, Rec A Recombinases, Recombination, Genetic, Sensitivity and Specificity, Ultraviolet Rays},
	issn = {0021-9258},
	doi = {10.1074/jbc.M109.004895},
	author = {Handa, Naofumi and Amitani, Ichiro and Gumlaw, Nathan and Sandler, Steven J and Kowalczykowski, Stephen C}
}
@article {808,
	title = {Suppression of constitutive SOS expression by recA4162 (I298V) and recA4164 (L126V) requires UvrD and RecX in Escherichia coli K-12.},
	journal = {Mol Microbiol},
	volume = {73},
	year = {2009},
	month = {2009 Jul},
	pages = {226-39},
	abstract = {Sensing DNA damage and initiation of genetic responses to repair DNA damage are critical to cell survival. In Escherichia coli, RecA polymerizes on ssDNA produced by DNA damage creating a RecA-DNA filament that interacts with the LexA repressor inducing the SOS response. RecA filament stability is negatively modulated by RecX and UvrD. recA730 (E38K) and recA4142 (F217Y) constitutively express the SOS response. recA4162 (I298V) and recA4164 (L126V) are intragenic suppressors of the constitutive SOS phenotype of recA730. Herein, it is shown that these suppressors are not allele specific and can suppress SOS(C) expression of recA730 and recA4142 in cis and in trans. recA4162 and recA4164 single mutants (and the recA730 and recA4142 derivatives) are Rec(+), UV(R) and are able to induce the SOS response after UV treatment like wild-type. UvrD and RecX are required for the suppression in two (recA730,4164 and recA4142,4162) of the four double mutants tested. To explain the data, one model suggests that recA(C) alleles promote SOS(C) expression by mimicking RecA filament structures that induce SOS and the suppressor alleles mimic RecA filament at end of SOS. UvrD and RecX are attracted to these latter structures to help dismantle or destabilize the RecA filament.},
	keywords = {Alleles, DNA Helicases, Escherichia coli, Escherichia coli Proteins, Gene Expression Regulation, Bacterial, Mutation, Missense, Rec A Recombinases, SOS Response (Genetics), Substrate Specificity},
	issn = {1365-2958},
	doi = {10.1111/j.1365-2958.2009.06765.x},
	author = {Long, Jarukit E and Renzette, Nicholas and Sandler, Steven J}
}
