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Science. 2014 Apr 4;344(6179):101-4. doi: 10.1126/science.1249094.

SRP RNA remodeling by SRP68 explains its role in protein translocation.

Author information

1
Heidelberg University Biochemistry Center (BZH), INF 328, D-69120 Heidelberg, Germany.

Abstract

The signal recognition particle (SRP) is central to membrane protein targeting; SRP RNA is essential for SRP assembly, elongation arrest, and activation of SRP guanosine triphosphatases. In eukaryotes, SRP function relies on the SRP68-SRP72 heterodimer. We present the crystal structures of the RNA-binding domain of SRP68 (SRP68-RBD) alone and in complex with SRP RNA and SRP19. SRP68-RBD is a tetratricopeptide-like module that binds to a RNA three-way junction, bends the RNA, and inserts an α-helical arginine-rich motif (ARM) into the major groove. The ARM opens the conserved 5f RNA loop, which in ribosome-bound SRP establishes a contact to ribosomal RNA. Our data provide the structural basis for eukaryote-specific, SRP68-driven RNA remodeling required for protein translocation.

PMID:
24700861
DOI:
10.1126/science.1249094
[Indexed for MEDLINE]
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