Insights into HIV-1 proviral transcription from integrative structure and dynamics of the Tat:AFF4:P-TEFb:TAR complex
Ursula Schulze-Gahmen,
Ignacia Echeverria,
Goran Stjepanovic,
Yun Bai,
Huasong Lu,
Dina Schneidman-Duhovny,
Jennifer A Doudna,
Qiang Zhou,
Andrej Sali,
James H Hurley
Affiliations
Ursula Schulze-Gahmen
Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States; California Institute of Quantitative Biosciences, University of California, Berkeley, Berkeley, United States
Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, San Francisco, United States; Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, United States; California Institute of Quantitative Biosciences, University of California San, Francisco, San Francisco, United States
Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States; California Institute of Quantitative Biosciences, University of California, Berkeley, Berkeley, United States; Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, United States
Yun Bai
Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States; California Institute of Quantitative Biosciences, University of California, Berkeley, Berkeley, United States
Huasong Lu
Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States; California Institute of Quantitative Biosciences, University of California, Berkeley, Berkeley, United States
Dina Schneidman-Duhovny
Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, San Francisco, United States; Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, United States; California Institute of Quantitative Biosciences, University of California San, Francisco, San Francisco, United States
Jennifer A Doudna
Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States; California Institute of Quantitative Biosciences, University of California, Berkeley, Berkeley, United States; Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, United States; Howard Hughes Medical Institute, University of California, Berkeley, Berkeley, United States; Department of Chemistry, University of California, Berkeley, Berkeley, United States
Qiang Zhou
Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States; California Institute of Quantitative Biosciences, University of California, Berkeley, Berkeley, United States
Andrej Sali
Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, San Francisco, United States; Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, United States; California Institute of Quantitative Biosciences, University of California San, Francisco, San Francisco, United States
Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States; California Institute of Quantitative Biosciences, University of California, Berkeley, Berkeley, United States; Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, United States
HIV-1 Tat hijacks the human superelongation complex (SEC) to promote proviral transcription. Here we report the 5.9 Å structure of HIV-1 TAR in complex with HIV-1 Tat and human AFF4, CDK9, and CycT1. The TAR central loop contacts the CycT1 Tat-TAR recognition motif (TRM) and the second Tat Zn2+-binding loop. Hydrogen-deuterium exchange (HDX) shows that AFF4 helix 2 is stabilized in the TAR complex despite not touching the RNA, explaining how it enhances TAR binding to the SEC 50-fold. RNA SHAPE and SAXS data were used to help model the extended (Tat Arginine-Rich Motif) ARM, which enters the TAR major groove between the bulge and the central loop. The structure and functional assays collectively support an integrative structure and a bipartite binding model, wherein the TAR central loop engages the CycT1 TRM and compact core of Tat, while the TAR major groove interacts with the extended Tat ARM.
