Directed evolution of novel polymerase activities: Mutation of a DNA polymerase into an efficient RNA polymerase

Gang Xia, Liangjing Chen, Takashi Sera, Ming Fa, Peter G. Schultz, Floyd E. Romesberg

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118 Citations (Scopus)


The creation of novel enzymatic function is of great interest, but remains a challenge because of the large sequence space of proteins. We have developed an activity-based selection method to evolve DNA polymerases with RNA polymerase activity. The Stoffel fragment (SF) of Thermus aquaticus DNA polymerase I is displayed on a filamentous phage by fusing it to a pill coat protein, and the substrate DNA template/primer duplexes are attached to other adjacent pill coat proteins. Phage particles displaying SF polymerases, which are able to extend the attached oligonucleotide primer by incorporating ribonucleoside triphosphates and biotinylated UTP, are immobilized to streptavidin-coated magnetic beads and subsequently recovered. After four rounds of screening an SF library, three SF mutants were isolated and shown to incorporate ribonucleoside triphosphates virtually as efficiently as the wild-type enzyme incorporates dNTP substrates.

Original languageEnglish
Pages (from-to)6597-6602
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number10
Publication statusPublished - May 14 2002
Externally publishedYes


ASJC Scopus subject areas

  • General

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