1fkj

<table><tr><td colspan='2'>[[1fkj]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/Human Human]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1FKJ OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1FKJ FirstGlance]. <br>

</td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=FK5:8-DEETHYL-8-[BUT-3-ENYL]-ASCOMYCIN'>FK5</scene></td></tr>

<tr id='activity'><td class="sblockLbl"><b>Activity:</b></td><td class="sblockDat"><span class='plainlinks'>[https://en.wikipedia.org/wiki/Peptidylprolyl_isomerase Peptidylprolyl isomerase], with EC number [https://www.brenda-enzymes.info/php/result_flat.php4?ecno=5.2.1.8 5.2.1.8] </span></td></tr>

[[https://www.uniprot.org/uniprot/FKB1A_HUMAN FKB1A_HUMAN]] Keeps in an inactive conformation TGFBR1, the TGF-beta type I serine/threonine kinase receptor, preventing TGF-beta receptor activation in absence of ligand. Recruites SMAD7 to ACVR1B which prevents the association of SMAD2 and SMAD3 with the activin receptor complex, thereby blocking the activin signal. May modulate the RYR1 calcium channel activity. PPIases accelerate the folding of proteins. It catalyzes the cis-trans isomerization of proline imidic peptide bonds in oligopeptides.<ref>PMID:9233797</ref> <ref>PMID:16720724</ref>

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== Publication Abstract from PubMed ==

FK506 (tacrolimus) is a natural product now approved in the US and Japan for organ transplantation. FK506, in complex with its 12 kDa cytosolic receptor (FKBP12), is a potent agonist of immunosuppression through the inhibition of the phosphatase activity of calcineurin. Rapamycin (sirolimus), which is itself an immunosuppressant by a different mechanism, completes with FK506 for binding to FKBP12 and thereby acts as an antagonist of calcineurin inhibition. We have solved the X-ray structure of unliganded FKBP12 and of FKBP12 in complex with FK506 and with rapamycin; these structures show localized differences in conformation and mobility in those regions of the protein that are known, by site-directed mutagenesis, to be involved in calcineurin inhibition. A comparison of 16 additional X-ray structures of FKBP12 in complex with FKBP12-binding ligands, where those structures were determined from different crystal forms with distinct packing arrangements, lends significance to the observed structural variability and suggests that it represents an intrinsic functional characteristic of the protein. Similar differences have been observed for FKBP12 before, but were considered artifacts of crystal-packing interactions. We suggest that immunosuppressive ligands express their differential effects in part by modulating the conformation of FKBP12, in agreement with mutagenesis experiments on the protein, and not simply through differences in the ligand structures themselves.

Comparative X-ray structures of the major binding protein for the immunosuppressant FK506 (tacrolimus) in unliganded form and in complex with FK506 and rapamycin.,Wilson KP, Yamashita MM, Sintchak MD, Rotstein SH, Murcko MA, Boger J, Thomson JA, Fitzgibbon MJ, Black JR, Navia MA Acta Crystallogr D Biol Crystallogr. 1995 Jul 1;51(Pt 4):511-21. PMID:15299838<ref>PMID:15299838</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>

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<div class="pdbe-citations 1fkj" style="background-color:#fffaf0;"></div>

[[Category: Human]]

[[Category: Navia, M A]]

[[Category: Sintchak, M D]]

[[Category: Thomson, J A]]

[[Category: Wilson, K P]]

[[Category: Rotamase]]