Solution structure of the Set2-Rpb1 interacting domain of human Set2 and its interaction with the hyperphosphorylated C-terminal domain of Rpb1.

Published

Journal Article

The phosphorylation state of the C-terminal repeat domain (CTD) of the largest subunit of RNA polymerase II changes as polymerase transcribes a gene, and the distinct forms of the phospho-CTD (PCTD) recruit different nuclear factors to elongating polymerase. The Set2 histone methyltransferase from yeast was recently shown to bind the PCTD of elongating RNA polymerase II by means of a novel domain termed the Set2-Rpb1 interacting (SRI) domain. Here, we report the solution structure of the SRI domain in human Set2 (hSRI domain), which adopts a left-turned three-helix bundle distinctly different from other structurally characterized PCTD-interacting domains. NMR titration experiments mapped the binding surface of the hSRI domain to helices 1 and 2, and Biacore binding studies showed that the domain binds preferably to [Ser-2 + Ser-5]-phosphorylated CTD peptides containing two or more heptad repeats. Point-mutagenesis studies identified five residues critical for PCTD binding. In view of the differential effects of these point mutations on binding to different CTD phosphopeptides, we propose a model for the hSRI domain interaction with the PCTD.

Full Text

Duke Authors

Cited Authors

  • Li, M; Phatnani, HP; Guan, Z; Sage, H; Greenleaf, AL; Zhou, P

Published Date

  • December 6, 2005

Published In

Volume / Issue

  • 102 / 49

Start / End Page

  • 17636 - 17641

PubMed ID

  • 16314571

Pubmed Central ID

  • 16314571

International Standard Serial Number (ISSN)

  • 0027-8424

Digital Object Identifier (DOI)

  • 10.1073/pnas.0506350102

Language

  • eng

Conference Location

  • United States