Recognition of different base tetrads by RHAU (DHX36): X-ray crystal structure of the G4 recognition motif bound to the 3'-end tetrad of a DNA G-quadruplex.
J Struct Biol
; 209(1): 107399, 2020 01 01.
Article
in En
| MEDLINE
| ID: mdl-31586599
ABSTRACT
G-quadruplexes (G4) are secondary structures of nucleic acids that can form in cells and have diverse biological functions. Several biologically important proteins interact with G-quadruplexes, of which RHAU (or DHX36) - a helicase from the DEAH-box superfamily, was shown to bind and unwind G-quadruplexes efficiently. We report a X-ray co-crystal structure at 1.5â¯Å resolution of an N-terminal fragment of RHAU bound to an exposed tetrad of a parallel-stranded G-quadruplex. The RHAU peptide folds into an L-shaped α-helix, and binds to a G-quadruplex through π-stacking and electrostatic interactions. X-ray crystal structure of our complex identified key amino acid residues important for G-quadruplex-peptide binding interaction at the 3'-end Gâ¢Gâ¢Gâ¢G tetrad. Together with previous solution and crystal structures of RHAU bound to the 5'-end Gâ¢Gâ¢Gâ¢G and Gâ¢Gâ¢Aâ¢T tetrads, our crystal structure highlights the occurrence of a robust G-quadruplex recognition motif within RHAU that can adapt to different accessible tetrads.
Key words
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
DNA-Binding Proteins
/
DEAD-box RNA Helicases
/
G-Quadruplexes
/
Nucleic Acid Conformation
Limits:
Humans
Language:
En
Journal:
J Struct Biol
Journal subject:
BIOLOGIA MOLECULAR
Year:
2020
Document type:
Article