View source for 1fmz


==CRYSTAL STRUCTURE OF A MUTANT WINGED BEAN CHYMOTRYPSIN INHIBITOR PROTEIN, N14K.==
<StructureSection load='1fmz' size='340' side='right'caption='[[1fmz]], [[Resolution|resolution]] 2.05&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[1fmz]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/Psophocarpus_tetragonolobus Psophocarpus tetragonolobus]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1FMZ OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1FMZ 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]] 2.05&#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=1fmz FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1fmz OCA], [https://pdbe.org/1fmz PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1fmz RCSB], [https://www.ebi.ac.uk/pdbsum/1fmz PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1fmz ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/ICW3_PSOTE ICW3_PSOTE] Inhibits alpha-chymotrypsin at the molar ratio of 1:2 in state of 1:1.
== Evolutionary Conservation ==
[[Image:Consurf_key_small.gif|200px|right]]
Check<jmol>
  <jmolCheckbox>
    <scriptWhenChecked>; select protein; define ~consurf_to_do selected; consurf_initial_scene = true; script "/wiki/ConSurf/fm/1fmz_consurf.spt"</scriptWhenChecked>
    <scriptWhenUnchecked>script /wiki/extensions/Proteopedia/spt/initialview03.spt</scriptWhenUnchecked>
    <text>to colour the structure by Evolutionary Conservation</text>
  </jmolCheckbox>
</jmol>, as determined by [http://consurfdb.tau.ac.il/ ConSurfDB]. You may read the [[Conservation%2C_Evolutionary|explanation]] of the method and the full data available from [http://bental.tau.ac.il/new_ConSurfDB/main_output.php?pdb_ID=1fmz ConSurf].
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== Publication Abstract from PubMed ==
A double-headed chymotrypsin inhibitor, WCI, from winged bean seeds was cloned for structural and biochemical studies. The inhibitor was subjected to two point mutations at a conserved position, Asn14. This residue, known to have a pivotal role in stabilizing the first reactive-site loop (Gln63-Phe68) of the inhibitor, is highly conserved in the sequences of the other members of Kunitz (STI) family as well as in the sequences of Kazal family of serine protease inhibitors. The mutants, N14K and N14D, were subjected to biochemical assay and their characteristics were compared with those of the recombinant inhibitor (rWCI). Crystallographic studies of the recombinant and the mutant proteins are discussed. These studies were primarily aimed at understanding the importance of the protein scaffolding towards the conformational rigidity of the reactive-site loop. Our analysis reveals that, as the Lys14 side chain takes an unusual fold in N14K and the Asp14 side chain in N14D interacts with the loop residues by water-mediated hydrogen bonds, the canonical conformation of the loop has remained effectively intact in both the mutant structures. However, minor alterations such as a 2-fold increase in the inhibitory affinity towards the cognate enzyme were observed.

The role of Asn14 in the stability and conformation of the reactive-site loop of winged bean chymotrypsin inhibitor: crystal structures of two point mutants Asn14--&gt;Lys and Asn14--&gt;Asp.,Ravichandran S, Dasgupta J, Chakrabarti C, Ghosh S, Singh M, Dattagupta JK Protein Eng. 2001 May;14(5):349-57. PMID:11438758<ref>PMID:11438758</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
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==See Also==
*[[Chymotrypsin inhibitor 3D structures|Chymotrypsin inhibitor 3D structures]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Large Structures]]
[[Category: Psophocarpus tetragonolobus]]
[[Category: Chakrabarti C]]
[[Category: Dasgupta J]]
[[Category: Dattagupta JK]]
[[Category: Ghosh S]]
[[Category: Ravichandran S]]