5rg5

<table><tr><td colspan='2'>[[5rg5]] is a 2 chain structure with sequence from [http://en.wikipedia.org/wiki/Theau Theau]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=5RG5 OCA]. For a <b>guided tour on the structure components</b> use [http://proteopedia.org/fgij/fg.htm?mol=5RG5 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>, <scene name='pdbligand=SO4:SULFATE+ION'>SO4</scene></td></tr>

<tr id='activity'><td class="sblockLbl"><b>Activity:</b></td><td class="sblockDat"><span class='plainlinks'>[http://en.wikipedia.org/wiki/Endo-1,4-beta-xylanase Endo-1,4-beta-xylanase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.2.1.8 3.2.1.8] </span></td></tr>

<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://proteopedia.org/fgij/fg.htm?mol=5rg5 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=5rg5 OCA], [http://pdbe.org/5rg5 PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=5rg5 RCSB], [http://www.ebi.ac.uk/pdbsum/5rg5 PDBsum], [http://prosat.h-its.org/prosat/prosatexe?pdbcode=5rg5 ProSAT]</span></td></tr>

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== Publication Abstract from PubMed ==

The creation of artificial enzymes is a key objective of computational protein design. Although de novo enzymes have been successfully designed, these exhibit low catalytic efficiencies, requiring directed evolution to improve activity. Here, we use room-temperature X-ray crystallography to study changes in the conformational ensemble during evolution of the designed Kemp eliminase HG3 (kcat/KM 146 M(-1)s(-1)). We observe that catalytic residues are increasingly rigidified, the active site becomes better pre-organized, and its entrance is widened. Based on these observations, we engineer HG4, an efficient biocatalyst (kcat/KM 103,000 M(-1)s(-1)) containing key first and second-shell mutations found during evolution. HG4 structures reveal that its active site is pre-organized and rigidified for efficient catalysis. Our results show how directed evolution circumvents challenges inherent to enzyme design by shifting conformational ensembles to favor catalytically-productive sub-states, and suggest improvements to the design methodology that incorporate ensemble modeling of crystallographic data.

 

== References ==

[[Category: Endo-1,4-beta-xylanase]]

[[Category: Broom, A]]

[[Category: Chica, R A]]

[[Category: Fraser, J S]]

[[Category: Rakotoharisoa, R V]]

[[Category: Thompson, M C]]

[[Category: Hydrolase]]