Gene Ontology annotation through association of InterPro records with GO terms
Gene Ontology annotation based on UniProtKB/Swiss-Prot keyword mapping
Combined Automated Annotation using Multiple IEA Methods
Single amino acid changes that alter the DNA sequence specificity of the DNA-[N6-adenine] methyltransferase (Dam) of bacteriophage T4.
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Characterized damh hypermethylating mutant (P126S)
"Hypermethylating mutants, damh, exhibit a relaxation in sequence specificity"
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Demonstrated T4 Dam recognizes GATC in both cytosine and hydroxymethylcytosine DNA
"Bacteriophage T4 codes for a DNA-[N6-adenine] methyltransferase (Dam) which recognizes primarily the sequence GATC in both cytosine- and hydroxymethylcytosine-containing DNA"
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Identified homology region III as involved in DNA sequence recognition
"These results implicate homology region III as a domain involved in DNA sequence recognition"
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damc mutant (F127V) methylates GATC in cytosine-DNA but not hmC-DNA
"damc, which methylates GATC in cytosine-containing DNA, but not in hydroxymethylcytosine-containing DNA"
Phage T4 DNA [N6-adenine]methyltransferase. Overexpression, purification, and characterization.
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Purified T4 Dam to near homogeneity
"was developed to purify the enzyme to near homogeneity"
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Determined enzyme is a monomer (s20,w = 3.0 S, Stokes radius = 23 A)
"The MTase has an s20,w of 3.0 S and a Stokes radius of 23 A and exists in solution as a monomer"
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Measured Km for AdoMet = 0.1 uM
"The Km for the methyl donor, S-adenosylmethionine, is 0.1 x 10(-6) M"
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Measured Km for DNA substrate = 1.1 x 10^-12 M
"the Km for substrate nonglucosylated, unmethylated T4 gt- dam DNA is 1.1 x 10(-12) M"
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Products (AdoHcy and methylated DNA) are competitive inhibitors
"The products of DNA methylation, S-adenosyl-L-homocysteine and methylated DNA, are competitive inhibitors of the reaction"
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T4 Dam methylates canonical GATC; can methylate GAY at high enzyme:DNA ratios
"T4 Dam methylates the palindromic tetranucleotide, GATC, designated the canonical sequence. However, at high MTase:DNA ratios, T4 Dam can methylate some noncanonical sequences"
A nomenclature for restriction enzymes, DNA methyltransferases, homing endonucleases and their genes.
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Provides nomenclature system for restriction enzymes and methyltransferases
"A nomenclature is described for restriction endonucleases, DNA methyltransferases, homing endonucleases and related genes"
Structure of the bacteriophage T4 DNA adenine methyltransferase.
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Solved crystal structure of T4 Dam in binary and ternary complexes
"We report here the crystal structures of the bacteriophage T4Dam DNA adenine methyltransferase (MTase) in a binary complex with the methyl-donor product S-adenosyl-L-homocysteine (AdoHcy) and in a ternary complex with a synthetic 12-bp DNA duplex and AdoHcy"
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Confirmed two-domain structure with catalytic and DNA binding domains
"T4Dam contains two domains: a seven-stranded catalytic domain that harbors the binding site for AdoHcy and a DNA binding domain"
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Two Dam monomers bind per DNA duplex in nonspecific mode
"the sequence-specific T4Dam bound to DNA in a nonspecific mode that contained two Dam monomers per synthetic duplex"
Transition from nonspecific to specific DNA interactions along the substrate-recognition pathway of dam methyltransferase.
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Characterized DNA recognition mechanism of Dam methyltransferase
"Three structures are described for bacteriophage T4 DNA-adenine methyltransferase (T4Dam) in ternary complexes with partially and fully specific DNA and a methyl-donor analog...We have identified two types of protein-DNA interactions: discriminatory contacts, which stabilize the transition state and accelerate methylation of the cognate site, and antidiscriminatory contacts"
Deep research summary for T4 Dam
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T4 Dam is an orphan methyltransferase without cognate restriction enzyme
"T4 Dam is explicitly an orphan methyltransferase (M.EcoT4Dam) that provides DNA protection without an associated restriction enzyme"
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Dam methylation protects phage DNA from host restriction systems
"By methylating GATC, T4 Dam participates in phage counter-defense against host restriction systems"