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Predictive motifs derived from cytosine methyltransferases
J Pósfai1, A S Bhagwat, G Pósfai
1Cold Spring Harbor Laboratory, NY 11724.
Nucleic Acids Research
|April 11, 1989
Summary
Five conserved motifs identify bacterial 5-methylcytosine DNA methyltransferases. These motifs also appear in mammalian enzymes and help discover new methyltransferases in genomic databases.
Area of Science:
- Molecular Biology
- Biochemistry
- Genomics
Background:
- DNA methyltransferases (MTases) are crucial enzymes involved in DNA modification.
- Bacterial 5-methylcytosine forming MTases share structural similarities.
- Identifying conserved regions is key to understanding enzyme function and classification.
Purpose of the Study:
- To identify conserved structural motifs within thirteen bacterial 5-methylcytosine forming DNA methyltransferases.
- To determine if these motifs can be used to distinguish these enzymes from other proteins.
- To explore the presence of these motifs in mammalian methyltransferases and identify novel MTases.
Main Methods:
- Sequence alignment and motif analysis of thirteen bacterial DNA methyltransferase sequences.
- Comparison of identified motifs against protein databases (PIR, GenBank, EMBL).
- Database searches for conserved motifs in unidentified open reading frames.
Main Results:
- Thirteen bacterial 5-methylcytosine forming MTases share conserved sequence blocks (motifs).
- Five highly conserved motifs were identified, including one containing the catalytic proline-cysteine dipeptide.
- These five motifs effectively distinguish 5-methylcytosine forming MTases from other known proteins and were found in a mammalian CG dinucleotide MTase.
Conclusions:
- The five conserved motifs are characteristic of 5-methylcytosine forming DNA methyltransferases.
- These motifs serve as reliable markers for identifying and classifying these enzymes.
- The study identified two potential novel 5-methylcytosine forming methyltransferases in genomic databases.