Biomaterial Database

The 30-kDa C-terminal domain of the RecB protein is critical for the nuclease activity, but not the helicase activity, of the RecBCD enzyme from Escherichia coli. 1998

M Yu, and J Souaya, and D A Julin

Department of Chemistry and Biochemistry, University of Maryland, College Park, MD 20742, USA.

The RecBCD enzyme from Escherichia coli is an ATP-dependent helicase and an ATP-stimulated nuclease. The 3' --> 5' exonuclease activity on double-stranded DNA is suppressed when the enzyme encounters a recombinational hot spot, called chi (chi). We have prepared a RecB deletion mutant (RecB1-929) by using results of limited proteolysis experiments that indicated that the RecB subunit consists of two main domains. The RecB1-929 protein, comprising the 100-kDa N-terminal domain of RecB, is an ATP-dependent helicase and a single-stranded DNA-dependent ATPase. Reconstitution of RecB1-929 with RecC and RecD leads to processive unwinding of a linearized plasmid. However, the reconstituted RecB1-929CD enzyme has lost the single-strand endo- and exonuclease and the double-strand exonuclease activities of the RecBCD enzyme. These results show that the 30-kDa C-terminal domain of RecB has an important role in the nuclease activity of RecBCD. On the basis of these findings, we propose the RecB C-terminal domain swing model to explain RecBCD's transformation from a 3' --> 5' exonuclease to a helicase when it meets a chi site.

UI	MeSH Term	Description	Entries
D008970	Molecular Weight	The sum of the weight of all the atoms in a molecule.	Molecular Weights,Weight, Molecular,Weights, Molecular
D004265	DNA Helicases	Proteins that catalyze the unwinding of duplex DNA during replication by binding cooperatively to single-stranded regions of DNA or to short regions of duplex DNA that are undergoing transient opening. In addition, DNA helicases are DNA-dependent ATPases that harness the free energy of ATP hydrolysis to translocate DNA strands.	ATP-Dependent DNA Helicase,DNA Helicase,DNA Unwinding Protein,DNA Unwinding Proteins,ATP-Dependent DNA Helicases,DNA Helicase A,DNA Helicase E,DNA Helicase II,DNA Helicase III,ATP Dependent DNA Helicase,ATP Dependent DNA Helicases,DNA Helicase, ATP-Dependent,DNA Helicases, ATP-Dependent,Helicase, ATP-Dependent DNA,Helicase, DNA,Helicases, ATP-Dependent DNA,Helicases, DNA,Protein, DNA Unwinding,Unwinding Protein, DNA,Unwinding Proteins, DNA
D004269	DNA, Bacterial	Deoxyribonucleic acid that makes up the genetic material of bacteria.	Bacterial DNA
D004706	Endodeoxyribonucleases	A group of enzymes catalyzing the endonucleolytic cleavage of DNA. They include members of EC 3.1.21.-, EC 3.1.22.-, EC 3.1.23.- (DNA RESTRICTION ENZYMES), EC 3.1.24.- (DNA RESTRICTION ENZYMES), and EC 3.1.25.-.
D004926	Escherichia coli	A species of gram-negative, facultatively anaerobic, rod-shaped bacteria (GRAM-NEGATIVE FACULTATIVELY ANAEROBIC RODS) commonly found in the lower part of the intestine of warm-blooded animals. It is usually nonpathogenic, but some strains are known to produce DIARRHEA and pyogenic infections. Pathogenic strains (virotypes) are classified by their specific pathogenic mechanisms such as toxins (ENTEROTOXIGENIC ESCHERICHIA COLI), etc.	Alkalescens-Dispar Group,Bacillus coli,Bacterium coli,Bacterium coli commune,Diffusely Adherent Escherichia coli,E coli,EAggEC,Enteroaggregative Escherichia coli,Enterococcus coli,Diffusely Adherent E. coli,Enteroaggregative E. coli,Enteroinvasive E. coli,Enteroinvasive Escherichia coli
D005090	Exodeoxyribonucleases	A family of enzymes that catalyze the exonucleolytic cleavage of DNA. It includes members of the class EC 3.1.11 that produce 5'-phosphomonoesters as cleavage products.	DNA Exonucleases,Exonucleases, DNA
D013329	Structure-Activity Relationship	The relationship between the chemical structure of a compound and its biological or pharmacological activity. Compounds are often classed together because they have structural characteristics in common including shape, size, stereochemical arrangement, and distribution of functional groups.	Relationship, Structure-Activity,Relationships, Structure-Activity,Structure Activity Relationship,Structure-Activity Relationships
D016297	Mutagenesis, Site-Directed	Genetically engineered MUTAGENESIS at a specific site in the DNA molecule that introduces a base substitution, or an insertion or deletion.	Mutagenesis, Oligonucleotide-Directed,Mutagenesis, Site-Specific,Oligonucleotide-Directed Mutagenesis,Site-Directed Mutagenesis,Site-Specific Mutagenesis,Mutageneses, Oligonucleotide-Directed,Mutageneses, Site-Directed,Mutageneses, Site-Specific,Mutagenesis, Oligonucleotide Directed,Mutagenesis, Site Directed,Mutagenesis, Site Specific,Oligonucleotide Directed Mutagenesis,Oligonucleotide-Directed Mutageneses,Site Directed Mutagenesis,Site Specific Mutagenesis,Site-Directed Mutageneses,Site-Specific Mutageneses
D017384	Sequence Deletion	Deletion of sequences of nucleic acids from the genetic material of an individual.	Deletion Mutation,Deletion Mutations,Deletion, Sequence,Deletions, Sequence,Mutation, Deletion,Mutations, Deletion,Sequence Deletions
D043211	Exodeoxyribonuclease V	An ATP-dependent exodeoxyribonuclease that cleaves in either the 5'- to 3'- or the 3'- to 5'-direction to yield 5'-phosphooligonucleotides. It is primarily found in BACTERIA.	ATP-Dependent DNase,Exodeoxyribonuclease V, alpha Chain,Exodeoxyribonuclease V, beta Chain,Exodeoxyribonuclease V, gamma Chain,Exonuclease V,RecBC DNase,RecBC Deoxyribonuclease,RecBCD Enzyme,ATP Dependent DNase,Deoxyribonuclease, RecBC