1as4

<table><tr><td colspan='2'>[[1as4]] is a 2 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=1AS4 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1AS4 FirstGlance]. <br>

</td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=ACT:ACETATE+ION'>ACT</scene></td></tr>

<tr id='gene'><td class="sblockLbl"><b>[[Gene|Gene:]]</b></td><td class="sblockDat">ACT ([https://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=9606 HUMAN])</td></tr>

[[https://www.uniprot.org/uniprot/AACT_HUMAN AACT_HUMAN]] Although its physiological function is unclear, it can inhibit neutrophil cathepsin G and mast cell chymase, both of which can convert angiotensin-1 to the active angiotensin-2.<ref>PMID:2404007</ref>

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== Publication Abstract from PubMed ==

Expressed in a kinetically trapped folding state, a serpin couples the thermodynamic driving force of a massive beta-sheet rearrangement to the inhibition of a target protease. Hence, the serpin-protease interaction is the premier example of a "spring-loaded" protein-protein interaction. Amino acid substitutions in the hinge region of a serpin reactive loop can weaken the molecular spring, which converts the serpin from an inhibitor into a substrate. To probe the molecular basis of this conversion, we report the crystal structure of A349R antichymotrypsin in the reactive loop cleaved state at 2.1 A resolution. This amino acid substitution does not block the beta-sheet rearrangement despite the burial of R349 in the hydrophobic core of the cleaved serpin along with a salt-linked acetate ion. The inhibitory activity of this serpin variant is not obliterated; remarkably, its inhibitory properties are anion-dependent due to the creation of an anion-binding cavity in the cleaved serpin.

Engineering an anion-binding cavity in antichymotrypsin modulates the "spring-loaded" serpin-protease interaction.,Lukacs CM, Rubin H, Christianson DW Biochemistry. 1998 Mar 10;37(10):3297-304. PMID:9521649<ref>PMID:9521649</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 1as4" style="background-color:#fffaf0;"></div>

[[Category: Human]]

[[Category: Christianson, D W]]

[[Category: Lukacs, C M]]

[[Category: Serpin]]