1NRJ

Signal Recognition Particle Receptor Beta-Subunit in Complex with the SRX Domain from the Alpha-Subunit

Summary for 1NRJ

• Entry DOI: 10.2210/pdb1nrj/pdb
• Descriptor: Signal recognition particle receptor alpha subunit homolog, Signal recognition particle receptor beta subunit, MAGNESIUM ION, ... (6 entities in total)
• Functional Keywords: signal recognition particle, transmembrane, receptor, endoplasmic reticulum, gtp-binding, gtpase-effector complex, protein transport
• Biological source: Saccharomyces cerevisiae (baker's yeast); More
• Cellular location: Endoplasmic reticulum membrane ; Peripheral membrane protein ; Cytoplasmic side : P32916; Endoplasmic reticulum membrane : P36057
• Total number of polymer chains: 2
• Total formula weight: 43389.33

Authors

Schwartz, T. (deposition date: 2003-01-24, release date: 2003-03-25, Last modification date: 2024-02-14)

Primary citation

Schwartz, T.,Blobel, G.
Structural Basis for the Function of the beta Subunit of the Eukaryotic Signal Recognition Particle Receptor
Cell(Cambridge,Mass.), 112:793-803, 2003

PubMed Abstract: Protein translocation across and insertion into membranes is a process essential to all life forms. In higher eukaryotes, this process is initiated by targeting the translating ribosome to the endoplasmic reticulum via the signal recognition particle (SRP) and its membrane-associated heterodimeric receptor (SR). This targeting step is regulated by three G proteins, SRP54, SR alpha, and SR beta, which act in concert. Little is known about the regulatory role of SR beta. Here, we present the 1.7 A crystal structure of the SR beta-GTP subunit in complex with the interaction domain of SR alpha. Strikingly, the binding interface overlaps largely with the switch 1 region of SR beta. This finding, together with additional biochemical data, shows that the eukaryotic SR is a conditional and not an obligate heterodimer. The results suggest that the GTP/GDP switch cycle of SR beta functions as a regulatory switch for the receptor dimerization. We discuss the implications for the translocation pathway.

PubMed: 12654246
DOI: 10.1016/S0092-8674(03)00161-2

Experimental method

X-RAY DIFFRACTION (1.7 Å)