1a57

<StructureSection load='1a57' size='340' side='right'caption='[[1a57]], [[NMR_Ensembles_of_Models | 20 NMR models]]' scene=''>

<table><tr><td colspan='2'>[[1a57]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/Buffalo_rat Buffalo rat]. Full experimental information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1A57 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1A57 FirstGlance]. <br>

</td></tr><tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=1a57 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1a57 OCA], [https://pdbe.org/1a57 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1a57 RCSB], [https://www.ebi.ac.uk/pdbsum/1a57 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1a57 ProSAT]</span></td></tr>

[[https://www.uniprot.org/uniprot/FABPI_RAT FABPI_RAT]] FABP are thought to play a role in the intracellular transport of long-chain fatty acids and their acyl-CoA esters. FABP2 is probably involved in triglyceride-rich lipoprotein synthesis. Binds saturated long-chain fatty acids with a high affinity, but binds with a lower affinity to unsaturated long-chain fatty acids. FABP2 may also help maintain energy homeostasis by functioning as a lipid sensor (By similarity).

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== Publication Abstract from PubMed ==

Intestinal fatty acid-binding protein (I-FABP) is a cytosolic 15.1-kDa protein that appears to function in the intracellular transport and metabolic trafficking of fatty acids. It binds a single molecule of long-chain fatty acid in an enclosed cavity surrounded by two five-stranded antiparallel beta-sheets and a helix-turn-helix domain. To investigate the role of the helical domain, we engineered a variant of I-FABP by deleting 17 contiguous residues and inserting a Ser-Gly linker (Kim K et al., 1996, Biochemistry 35:7553-7558). This variant, termed delta17-SG, was remarkably stable, exhibited a high beta-sheet content and was able to bind fatty acids with some features characteristic of the wild-type protein. In the present study, we determined the structure of the delta17-SG/palmitate complex at atomic resolution using triple-resonance 3D NMR methods. Sequence-specific 1H, 13C, and 15N resonance assignments were established at pH 7.2 and 25 degrees C and used to define the consensus 1H/13C chemical shift-derived secondary structure. Subsequently, an iterative protocol was used to identify 2,544 NOE-derived interproton distance restraints and to calculate its tertiary structure using a unique distance geometry/simulated annealing algorithm. In spite of the sizable deletion, the delta17-SG structure exhibits a backbone conformation that is nearly superimposable with the beta-sheet domain of the wild-type protein. The selective deletion of the alpha-helical domain creates a very large opening that connects the interior ligand-binding cavity with exterior solvent. Unlike wild-type I-FABP, fatty acid dissociation from delta17-SG is structurally and kinetically unimpeded, and a protein conformational transition is not required. The delta17-SG variant of I-FABP is the only wild-type or engineered member of the intracellular lipid-binding protein family whose structure lacks alpha-helices. Thus, delta17-SG I-FABP constitutes a unique model system for investigating the role of the helical domain in ligand-protein recognition, protein stability and folding, lipid transfer mechanisms, and cellular function.

The three-dimensional structure of a helix-less variant of intestinal fatty acid-binding protein.,Steele RA, Emmert DA, Kao J, Hodsdon ME, Frieden C, Cistola DP Protein Sci. 1998 Jun;7(6):1332-9. PMID:9655337<ref>PMID:9655337</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 1a57" style="background-color:#fffaf0;"></div>

== References ==

<references/>

[[Category: Buffalo rat]]

[[Category: Cistola, D P]]

[[Category: Emmert, D A]]

[[Category: Frieden, C]]

[[Category: Hodsdon, M E]]

[[Category: Kao, J]]

[[Category: Steele, R A]]

[[Category: Lipocalin]]