Multimeric assembly and biochemical characterization of the Trax-translin endonuclease complex

Journal Article · Fri Sep 16 04:00:00 EDT 2011 · Nature Structural & Molecular Biology

DOI:https://doi.org/10.1038/nsmb.2069· OSTI ID:1020589

Tian, Yuan; Simanshu, Dhirendra K; Ascano, Manuel; Diaz-Avalos, Ruben; Park, Ah Young; Juranek, Stefan A; Rice, William J; Yin, Qian; Robinson, Carol V; Tuschl, Thomas; Patel, Dinshaw J ^[1]

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1. Weill-Med

Trax-Translin heteromers, also known as C3PO, have been proposed to activate the RNA-induced silencing complex (RISC) by facilitating endonucleolytic cleavage of the siRNA passenger strand. We report on the crystal structure of hexameric Drosophila C3PO formed by truncated translin and Trax, along with electron microscopic and mass spectrometric studies on octameric C3PO formed by full-length translin and Trax. Our studies establish that Trax adopts the translin fold, possesses catalytic centers essential for C3PO's endoRNase activity and interacts extensively with translin to form an octameric assembly. The catalytic pockets of Trax subunits are located within the interior chamber of the octameric scaffold. Truncated C3PO, like full-length C3PO, shows endoRNase activity that leaves 3'-hydroxyl-cleaved ends. We have measured the catalytic activity of C3PO and shown it to cleave almost stoichiometric amounts of substrate per second.

• Research Organization: Advanced Photon Source (APS), Argonne National Laboratory (ANL), Argonne, IL (US)
• Sponsoring Organization: NIHHHMI
• OSTI ID: 1020589
• Journal Information: Nature Structural & Molecular Biology, Journal Name: Nature Structural & Molecular Biology Journal Issue: (6) ; 06, 2011 Vol. 18; ISSN 1545-9993
• Publisher: Nature Publishing Group
• Country of Publication: United States
• Language: ENGLISH

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
99 GENERAL AND MISCELLANEOUS
CLEAVAGE
CRYSTAL STRUCTURE
DROSOPHILA
ELECTRONS
ENDONUCLEASES
OCCUPANTS
SUBSTRATES