View source for 5jb4


==A simplified BPTI variant containing 21 alanines out 58 of residues==
<StructureSection load='5jb4' size='340' side='right'caption='[[5jb4]], [[Resolution|resolution]] 1.99&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[5jb4]] is a 3 chain structure with sequence from [https://en.wikipedia.org/wiki/Bos_taurus Bos taurus]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=5JB4 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=5JB4 FirstGlance]. <br>
</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">X-ray diffraction, [[Resolution|Resolution]] 1.99&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=SO4:SULFATE+ION'>SO4</scene></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=5jb4 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=5jb4 OCA], [https://pdbe.org/5jb4 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=5jb4 RCSB], [https://www.ebi.ac.uk/pdbsum/5jb4 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=5jb4 ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/BPT1_BOVIN BPT1_BOVIN] Inhibits trypsin, kallikrein, chymotrypsin, and plasmin.
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== Publication Abstract from PubMed ==
We report a thermodynamic and structural analysis of six extensively simplified bovine pancreatic trypsin inhibitor (BPTI) variants containing 19-24 alanines out of 58 residues. Differential scanning calorimetry indicated a two-state thermal unfolding, typical of a native protein with densely packed interior. Surprisingly, increasing the number of alanines induced enthalpy stabilization, which was however over-compensated by entropy destabilization. X-ray crystallography indicated that the alanine substitutions caused the recruitment of novel water molecules facilitating the formation of protein-water hydrogen bonds and improving the hydration shells around the alanine's methyl groups, both of which presumably contributed to enthalpy stabilization. There was a strong correlation between the number of water molecules and the thermodynamic parameters. Overall, our results demonstrate that, in contrast to our initial expectation, a protein sequence in which over 40% of the residues are alanines can retain a densely packed structure and undergo thermal denaturation with a large enthalpy change, mainly contributed by hydration.

Crystal structures of highly simplified BPTIs provide insights into hydration-driven increase of unfolding enthalpy.,Islam MM, Yohda M, Kidokoro SI, Kuroda Y Sci Rep. 2017 Mar 7;7:41205. doi: 10.1038/srep41205. PMID:28266637<ref>PMID:28266637</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 5jb4" style="background-color:#fffaf0;"></div>

==See Also==
*[[BPTI 3D structures|BPTI 3D structures]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Bos taurus]]
[[Category: Large Structures]]
[[Category: Islam MM]]