G-quadruplex binding ability of TLS/FUS depends on the ?-spiral structure of the RGG domain.

ABSTRACT: The RGG domain, defined as closely spaced Arg-Gly-Gly repeats, is a DNA and RNA-binding domain in various nucleic acid-binding proteins. Translocated in liposarcoma (TLS), which is also called FUS, is a protein with three RGG domains, RGG1, RGG2 and RGG3. TLS/FUS binding to G-quadruplex telomere DNA and telomeric repeat-containing RNA depends especially on RGG3, comprising Arg-Gly-Gly repeats with proline- and arginine-rich regions. So far, however, only non-specific DNA and RNA binding of TLS/FUS purified with buffers containing urea and KCl have been reported. Here, we demonstrate that protein purification using a buffer with high concentrations of urea and KCl decreases the G-quadruplex binding abilities of TLS/FUS and RGG3, and disrupts the ?-spiral structure of RGG3. Moreover, the Arg-Gly-Gly repeat region in RGG3 by itself cannot form a stable ?-spiral structure that binds to the G-quadruplex, because the proline- and arginine-rich regions induce the ?-spiral structure and the G-quadruplex-binding ability of RGG3. Our findings suggest that the G-quadruplex-specific binding abilities of TLS/FUS require RGG3 with a ?-spiral structure stabilized by adjacent proline- and arginine-regions.

SUBMITTER: Yagi R 

PROVIDER: S-EPMC6159513 | biostudies-literature | 2018 Jul

REPOSITORIES: biostudies-literature