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Title
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Mutational analysis of mammalian poly(A) polymerase identifies a region for primer binding and catalytic domain, homologous to the family X polymerases, and to other nucleotidyltransferases.
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Authors
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G.Martin,
W.Keller.
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Ref.
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Embo J, 1996,
15,
2593-2603.
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PubMed id
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Abstract
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We have tested deletion and substitution mutants of bovine poly(A) polymerase,
and have identified a small region that overlaps with a nuclear localization
signal and binds to the RNA primer. Systematic mutagenesis of carboxylic amino
acids led to the identification of three aspartates that are essential for
catalysis. Sequence and secondary structure comparisons of regions surrounding
these aspartates with sequences of other polymerases revealed a significant
homology to the palm structure of DNA polymerase beta, terminal
deoxynucleotidyltransferase and DNA polymerase IV of Saccharomyces cerevisiae,
all members of the family X of polymerases. This homology extends as far as cca:
tRNA nucleotidyltransferase and streptomycin adenylyltransferase, an antibiotic
resistance factor.
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