@article {812,
	title = {RecA-mediated SOS induction requires an extended filament conformation but no ATP hydrolysis.},
	journal = {Mol Microbiol},
	volume = {69},
	year = {2008},
	month = {2008 Sep},
	pages = {1165-79},
	abstract = {The Escherichia coli SOS response to DNA damage is modulated by the RecA protein, a recombinase that forms an extended filament on single-stranded DNA and hydrolyzes ATP. The RecA K72R (recA2201) mutation eliminates the ATPase activity of RecA protein. The mutation also limits the capacity of RecA to form long filaments in the presence of ATP. Strains with this mutation do not undergo SOS induction in vivo. We have combined the K72R variant of RecA with another mutation, RecA E38K (recA730). In vitro, the double mutant RecA E38K/K72R (recA730,2201) mimics the K72R mutant protein in that it has no ATPase activity. The double mutant protein will form long extended filaments on ssDNA and facilitate LexA cleavage almost as well as wild-type, and do so in the presence of ATP. Unlike recA K72R, the recA E38K/K72R double mutant promotes SOS induction in vivo after UV treatment. Thus, SOS induction does not require ATP hydrolysis by the RecA protein, but does require formation of extended RecA filaments. The RecA E38K/K72R protein represents an improved reagent for studies of the function of ATP hydrolysis by RecA in vivo and in vitro.},
	keywords = {Adenosine Triphosphate, Amino Acid Substitution, Bacterial Proteins, DNA, Bacterial, DNA, Single-Stranded, Escherichia coli, Escherichia coli Proteins, Hydrolysis, Rec A Recombinases, Serine Endopeptidases, SOS Response (Genetics), Ultraviolet Rays},
	issn = {1365-2958},
	doi = {10.1111/j.1365-2958.2008.06341.x},
	author = {Gruenig, Marielle C and Renzette, Nicholas and Long, Edward and Chitteni-Pattu, Sindhu and Inman, Ross B and Cox, Michael M and Sandler, Steven J}
}
@article {813,
	title = {Requirements for ATP binding and hydrolysis in RecA function in Escherichia coli.},
	journal = {Mol Microbiol},
	volume = {67},
	year = {2008},
	month = {2008 Mar},
	pages = {1347-59},
	abstract = {RecA is essential for recombination, DNA repair and SOS induction in Escherichia coli. ATP hydrolysis is known to be important for RecA{\textquoteright}s roles in recombination and DNA repair. In vitro reactions modelling SOS induction minimally require ssDNA and non-hydrolyzable ATP analogues. This predicts that ATP hydrolysis will not be required for SOS induction in vivo. The requirement of ATP binding and hydrolysis for SOS induction in vivo is tested here through the study of recA4159 (K72A) and recA2201 (K72R). RecA4159 is thought to have reduced affinity for ATP. RecA2201 binds, but does not hydrolyse ATP. Neither mutant was able to induce SOS expression after UV irradiation. RecA2201, unlike RecA4159, could form filaments on DNA and storage structures as measured with RecA-GFP. RecA2201 was able to form hybrid filaments and storage structures and was either recessive or dominant to RecA(+), depending on the ratio of the two proteins. RecA4159 was unable to enter RecA(+) filaments on DNA or storage structures and was recessive to RecA(+). It is concluded that ATP hydrolysis is essential for SOS induction. It is proposed that ATP binding is essential for storage structure formation and ability to interact with other RecA proteins in a filament.},
	keywords = {Adenosine Triphosphate, Chromosomes, Bacterial, Escherichia coli, Escherichia coli Proteins, Hydrolysis, Mutation, Protein Binding, Rec A Recombinases, Ultraviolet Rays},
	issn = {1365-2958},
	doi = {10.1111/j.1365-2958.2008.06130.x},
	author = {Renzette, Nicholas and Sandler, Steven J}
}
@article {398,
	title = {Proteolytic degradation of Escherichia coli transcription activators SoxS and MarA as the mechanism for reversing the induction of the superoxide (SoxRS) and multiple antibiotic resistance (Mar) regulons.},
	journal = {Mol Microbiol},
	volume = {51},
	year = {2004},
	month = {2004 Mar},
	pages = {1801-16},
	abstract = {In Escherichia coli, the SoxRS regulon confers resistance to redox-cycling compounds, and the Mar regulon provides a defence against multiple antibiotics. The response regulators, SoxS and MarA, are synthesized de novo in response to their inducing signals and directly activate transcription of a common set of target genes. Although the mechanisms of transcription activation by SoxS and MarA have been well studied, little is known about how the systems are shut-off once the inducing stress has subsided, except that de novo synthesis of the regulators is known to cease almost immediately. Here, we induced the SoxRS regulon and determined that, upon removal of the inducer, expression of the regulon{\textquoteright}s genes quickly returns to the preinduced level. This rapid shut-off indicates that the system is reset by an active process. We found that SoxS is unstable and infer that SoxS degradation is responsible for the rapid return of the system to the ground state upon removal of the inducing signal. We also found that MarA is unstable and that the instability of both proteins is intrinsic and unregulated. We used null mutations of protease genes to identify the proteases involved in the degradation of SoxS and MarA. Among single protease mutations, only lon mutations increased the half-life of SoxS and MarA. In addition, SoxS appeared to be nearly completely stable in a lon ftsH double mutant. Using hexahistidine tags placed at the respective ends of the activators, we found that access to the amino-terminus is essential for the proteolytic degradation.},
	keywords = {Base Sequence, Blotting, Western, DNA Primers, DNA-Binding Proteins, Drug Resistance, Bacterial, Drug Resistance, Multiple, Bacterial, Endopeptidases, Escherichia coli, Escherichia coli Proteins, Genes, Bacterial, Half-Life, Hydrolysis, Kinetics, Mutation, Oxidation-Reduction, Promoter Regions, Genetic, Regulon, Trans-Activators, Transcription, Genetic},
	issn = {0950-382X},
	author = {Griffith, Kevin L and Shah, Ishita M and Wolf, Richard E}
}
@article {1198,
	title = {Determination of polydextrose as dietary fiber in foods.},
	journal = {J AOAC Int},
	volume = {83},
	year = {2000},
	month = {2000 Jul-Aug},
	pages = {1006-12},
	abstract = {<p>Polydextrose (Litesse) provides physiological effects consistent with dietary fiber. However, AOAC methods for measuring total dietary fiber (TDF) in foods include an ethanol precipitation step in which polydextrose and similar carbohydrates are discarded and therefore not quantitated. This study describes a method developed to quantitate polydextrose in foods. The new method includes water extraction, centrifugal ultrafiltration, multienzyme hydrolysis, and anion exchange chromatography with electrochemical detection. Six foods were prepared with 4 levels of polydextrose to test the ruggedness of the method. Internal validation demonstrated the ruggedness of the method with recoveries ranging from 83 to 104\% with an average of 95\% (n = 24) and relative standard deviation of recoveries ranging from 0.7 to 13\% with an average of 3.3\% (n = 24). The value is added to that obtained for dietary fiber content of foods using the AOAC methods, to determine the TDF content of the food.</p>},
	keywords = {Animals, Anions, Bacterial Proteins, Beverages, Cacao, Candy, Chromatography, Ion Exchange, Dietary Fiber, Ethanol, Food Analysis, Glucan 1,4-alpha-Glucosidase, Glucans, Glycoside Hydrolases, Humans, Hydrolysis, Isoamylase, Tea, Ultrafiltration},
	issn = {1060-3271},
	author = {Craig, S A and Holden, J F and Khaled, M Y and Craig, S A and Holden, J F and Khaled, M Y}
}
@article {863,
	title = {Enzymatic hydrolysis of oligomeric models of poly-3-hydroxybutyrate.},
	journal = {Biomacromolecules},
	volume = {1},
	year = {2000},
	month = {2000 Winter},
	pages = {577-83},
	abstract = {The mechanism of the enzymatic degradation of poly([R]-3-hydroxybutyrate) (PHB) was investigated by using well-defined model substrates, including both linear and cyclic [R]-3-hydroxybutyrate (3HB) and [R]-3-hydroxyvalerate (3HV) oligomers, with two different PHB depolymerases. The linear and cyclic oligomers containing from 2 to 10 repeating units were hydrolyzed in solutions of the depolymerase isolated from Aspergillus fumigatus and Alcaligenes faecalis, and the rates of hydrolysis and types of products formed were characterized. Both of the depolymerases catalyzed the hydrolysis of the cyclic oligomers (macrolides) which contained more than three 3HB and 3HV repeating units. The degradation reactions of the linear and cyclic 3HB oligomers with the A. fumigatus depolymerase gave similar ratios of monomer-to-dimer products, but PHB itself formed mostly monomer on hydrolysis, indicating that the enzymatic hydrolysis reactions occurred by different mechanisms for these different types of substrates. The results of this study conclusively show that at least the endo mode of polymer hydrolysis occurs with the two enzymes studied, while the A. fumigatus depolymerase was found to utilize both endo and exo modes of hydrolysis to efficiently degrade PHB and 3HB oligomers.},
	keywords = {3-Hydroxybutyric Acid, Alcaligenes, Aspergillus fumigatus, Carboxylic Ester Hydrolases, Escherichia coli, Hydrolysis, Kinetics, Macrolides, Models, Chemical, Polymers},
	issn = {1525-7797},
	author = {Scherer, T M and Fuller, R C and Goodwin, S and Lenz, R W}
}
