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Structural basis of transcription: role of the trigger loop in substrate specificity and catalysis.

ABSTRACT: New structures of RNA polymerase II (pol II) transcribing complexes reveal a likely key to transcription. The trigger loop swings beneath a correct nucleoside triphosphate (NTP) in the nucleotide addition site, closing off the active center and forming an extensive network of interactions with the NTP base, sugar, phosphates, and additional pol II residues. A histidine side chain in the trigger loop, precisely positioned by these interactions, may literally "trigger" phosphodiester bond formation. Recognition and catalysis are thus coupled, ensuring the fidelity of transcription.

SUBMITTER: Wang D

PROVIDER: S-EPMC1876690 | biostudies-literature | 2006 Dec

REPOSITORIES: biostudies-literature

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Structural basis of transcription: role of the trigger loop in substrate specificity and catalysis.

Wang Dong D Bushnell David A DA Westover Kenneth D KD Kaplan Craig D CD Kornberg Roger D RD

Cell 20061201 5

New structures of RNA polymerase II (pol II) transcribing complexes reveal a likely key to transcription. The trigger loop swings beneath a correct nucleoside triphosphate (NTP) in the nucleotide addition site, closing off the active center and forming an extensive network of interactions with the NTP base, sugar, phosphates, and additional pol II residues. A histidine side chain in the trigger loop, precisely positioned by these interactions, may literally "trigger" phosphodiester bond formatio ...[more]

PMID: 17129781

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