4gd9: Difference between revisions

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-{{STRUCTURE_4gd9|  PDB=4gd9  |  SCENE=  }}
+==Circular Permuted Streptavidin N49/G48==
-===Circular Permuted Streptavidin N49/G48===
+<StructureSection load='4gd9' size='340' side='right' caption='[[4gd9]], [[Resolution|resolution]] 1.50&Aring;' scene=''>
-{{ABSTRACT_PUBMED_23695241}}
+== Structural highlights ==
+<table><tr><td colspan='2'>[[4gd9]] is a 4 chain structure with sequence from [http://en.wikipedia.org/wiki/Streptomyces_avidinii Streptomyces avidinii]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=4GD9 OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=4GD9 FirstGlance]. <br>
+</td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat"><scene name='pdbligand=BTN:BIOTIN'>BTN</scene>, <scene name='pdbligand=SO4:SULFATE+ION'>SO4</scene></td></tr>
+<tr id='related'><td class="sblockLbl"><b>[[Related_structure|Related:]]</b></td><td class="sblockDat">[[1swf|1swf]]</td></tr>
+<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=4gd9 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=4gd9 OCA], [http://www.rcsb.org/pdb/explore.do?structureId=4gd9 RCSB], [http://www.ebi.ac.uk/pdbsum/4gd9 PDBsum]</span></td></tr>
+</table>
+== Function ==
+[[http://www.uniprot.org/uniprot/SAV_STRAV SAV_STRAV]] The biological function of streptavidin is not known. Forms a strong non-covalent specific complex with biotin (one molecule of biotin per subunit of streptavidin).
+<div style="background-color:#fffaf0;">
+== Publication Abstract from PubMed ==
+Circular permutation of streptavidin was carried out in order to investigate the role of a main-chain amide in stabilizing the high-affinity complex of the protein and biotin. Mutant proteins CP49/48 and CP50/49 were constructed to place new N-termini at residues 49 and 50 in a flexible loop involved in stabilizing the biotin complex. Crystal structures of the two mutants show that half of each loop closes over the binding site, as observed in wild-type streptavidin, while the other half adopts the open conformation found in the unliganded state. The structures are consistent with kinetic and thermodynamic data and indicate that the loop plays a role in enthalpic stabilization of the bound state via the Asn49 amide-biotin hydrogen bond. In wild-type streptavidin, the entropic penalties of immobilizing a flexible portion of the protein to enhance binding are kept to a manageable level by using a contiguous loop of medium length (six residues) which is already constrained by its anchorage to strands of the beta-barrel protein. A molecular-dynamics simulation for CP50/49 shows that cleavage of the binding loop results in increased structural fluctuations for Ser45 and that these fluctuations destabilize the streptavidin-biotin complex.
-==Function==
+Structural consequences of cutting a binding loop: two circularly permuted variants of streptavidin.,Le Trong I, Chu V, Xing Y, Lybrand TP, Stayton PS, Stenkamp RE Acta Crystallogr D Biol Crystallogr. 2013 Jun;69(Pt 6):968-77. doi:, 10.1107/S0907444913003855. Epub 2013 May 11. PMID:23695241<ref>PMID:23695241</ref>
-[[http://www.uniprot.org/uniprot/SAV_STRAV SAV_STRAV]] The biological function of streptavidin is not known. Forms a strong non-covalent specific complex with biotin (one molecule of biotin per subunit of streptavidin).
-==About this Structure==
+From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
-[[4gd9]] is a 4 chain structure with sequence from [http://en.wikipedia.org/wiki/Streptomyces_avidinii Streptomyces avidinii]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=4GD9 OCA].
+</div>
-==Reference==
+==See Also==
-<ref group="xtra">PMID:023695241</ref><references group="xtra"/><references/>
+*[[Avidin|Avidin]]
+== References ==
+<references/>
+__TOC__
+</StructureSection>
 [[Category: Streptomyces avidinii]]
-[[Category: Chu, V.]]
+[[Category: Chu, V]]
-[[Category: Lybrand, T P.]]
+[[Category: Lybrand, T P]]
 [[Category: Stayton, P S]]
-[[Category: Stenkamp, R E.]]
+[[Category: Stenkamp, R E]]
-[[Category: Trong, I Le.]]
+[[Category: Trong, I Le]]
-[[Category: Xing, Y.]]
+[[Category: Xing, Y]]
 [[Category: Biotin]]
 [[Category: Biotin-binding protein]]
 [[Category: Circular permutation]]