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The phage RNA polymerases are related to DNA polymerases and reverse transcriptases
1Department of Microbiology and Immunology, Morse Institute of Molecular Genetics, SUNY Health Science Center at Brooklyn 11203-2098.
Molecular Microbiology
|October 1, 1993
Summary
The T7 bacteriophage RNA polymerase (RNAP) is a simple enzyme structurally related to other nucleotide polymerases. This review covers its structure, function, and evolutionary connections.
Area of Science:
- Biochemistry
- Molecular Biology
- Structural Biology
Background:
- The single-subunit DNA-dependent RNA polymerase (RNAP) from bacteriophage T7 serves as a model for related enzymes.
- These include RNAPs from phages T3 and SP6, and mitochondrial RNAPs.
- Structural and functional studies of T7 RNAP have advanced our understanding of its catalytic mechanisms.
Purpose of the Study:
- To review the structure and function of bacteriophage T7 RNAP.
- To present evidence supporting its classification within a broader family of nucleotide polymerases.
- To highlight the evolutionary relationships between phage-like RNAPs and other polymerases.
Main Methods:
- Crystallographic analysis of T7 RNAP.
- Genetic and biochemical characterization of T7 RNAP.
- Comparative analysis of T7 RNAP with other nucleotide polymerases.
Main Results:
- The crystal structure of T7 RNAP provides insights into its catalytic site and substrate binding.
- Genetic and biochemical data support a conserved mechanism of action across related RNAPs.
- Sequence and structural similarities link T7 RNAP to DNA polymerases, RNA-dependent RNA polymerases, and reverse transcriptases.
Conclusions:
- T7 RNAP is a structurally conserved enzyme with implications for understanding polymerase evolution.
- The enzyme's simplicity and well-defined structure make it an excellent model for studying fundamental polymerase mechanisms.
- Evidence supports the assignment of T7 RNAP to a broader superfamily of nucleotide-utilizing enzymes.