2ged
From Proteopedia
(New page: 200px<br /><applet load="2ged" size="450" color="white" frame="true" align="right" spinBox="true" caption="2ged, resolution 2.20Å" /> '''Signal Recognition P...) |
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| - | [[Image:2ged.gif|left|200px]]<br /><applet load="2ged" size=" | + | [[Image:2ged.gif|left|200px]]<br /><applet load="2ged" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="2ged, resolution 2.20Å" /> | caption="2ged, resolution 2.20Å" /> | ||
'''Signal Recognition Particle Receptor Beta-Subunit in nucleotide-free dimerized form'''<br /> | '''Signal Recognition Particle Receptor Beta-Subunit in nucleotide-free dimerized form'''<br /> | ||
==Overview== | ==Overview== | ||
| - | Protein translocation across and insertion into membranes is essential to | + | 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== | ==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 SO4 as [http://en.wikipedia.org/wiki/ligand ligand]. Full crystallographic information is available from [http:// | + | 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== | ==Reference== | ||
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[[Category: Single protein]] | [[Category: Single protein]] | ||
[[Category: Schmidt, D.]] | [[Category: Schmidt, D.]] | ||
| - | [[Category: Schwartz, T | + | [[Category: Schwartz, T U.]] |
[[Category: SO4]] | [[Category: SO4]] | ||
[[Category: circular permutation]] | [[Category: circular permutation]] | ||
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[[Category: signal recognition particle]] | [[Category: signal recognition particle]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 17:30:50 2008'' |
Revision as of 15:30, 21 February 2008
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Signal Recognition Particle Receptor Beta-Subunit in nucleotide-free dimerized form
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 Single protein structure of sequence from Saccharomyces cerevisiae with as ligand. Full crystallographic information is available from 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:16627619
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