View source for 2ged

[[Image:2ged.gif|left|200px]]<br /><applet load="2ged" size="350" color="white" frame="true" align="right" spinBox="true" 
caption="2ged, resolution 2.20&Aring;" />
'''Signal Recognition Particle Receptor Beta-Subunit in nucleotide-free dimerized form'''<br />

==Overview==
Protein translocation across and insertion into membranes is essential to all life forms. Signal peptide-bearing nascent polypeptide chains emerging from the ribosome are first sampled by the signal-recognition particle (SRP), then targeted to the membrane via the SRP receptor (SR), and, finally, transferred to the protein-conducting channel. In eukaryotes, this process is tightly controlled by the concerted action of three G proteins, the 54-kD subunit of SRP and the alpha- and beta-subunits of SR. We have determined the 2.2-A crystal structure of the nucleotide-free SRbeta domain. Unexpectedly, the structure is a homodimer with a highly intertwined interface made up of residues from the switch regions of the G domain. The remodeling of the switch regions does not resemble any of the known G protein switch mechanisms. Biochemical analysis confirms homodimerization in vitro, which is incompatible with SRalpha binding. The switch mechanism involves cis/trans isomerization of a strictly conserved proline, potentially implying a new layer of regulation of cotranslational transport.

==About this Structure==
2GED is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Saccharomyces_cerevisiae Saccharomyces cerevisiae] with <scene name='pdbligand=SO4:'>SO4</scene> as [http://en.wikipedia.org/wiki/ligand ligand]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2GED OCA]. 

==Reference==
Homodimerization of the G protein SRbeta in the nucleotide-free state involves proline cis/trans isomerization in the switch II region., Schwartz TU, Schmidt D, Brohawn SG, Blobel G, Proc Natl Acad Sci U S A. 2006 May 2;103(18):6823-8. Epub 2006 Apr 20. PMID:[http://ispc.weizmann.ac.il//pmbin/getpm?pmid=16627619 16627619]
[[Category: Saccharomyces cerevisiae]]
[[Category: Single protein]]
[[Category: Schmidt, D.]]
[[Category: Schwartz, T U.]]
[[Category: SO4]]
[[Category: circular permutation]]
[[Category: g protein]]
[[Category: proline isomerization]]
[[Category: protein transport]]
[[Category: signal recognition particle]]

''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 17:30:50 2008''