View source for 24nk


==Crystal Structure of Cypridina Luciferase complexed with Oxyluciferin==
<StructureSection load='24nk' size='340' side='right'caption='[[24nk]], [[Resolution|resolution]] 3.14&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[24nk]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/Cypridina_noctiluca Cypridina noctiluca]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=24NK OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=24NK 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]] 3.14&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=A1L7I:(2~{S})-~{N}-[3-[3-[bis(azanyl)methylideneamino]propyl]-5-(1~{H}-indol-3-yl)pyrazin-2-yl]-2-methyl-butanamide'>A1L7I</scene>, <scene name='pdbligand=NAG:N-ACETYL-D-GLUCOSAMINE'>NAG</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=24nk FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=24nk OCA], [https://pdbe.org/24nk PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=24nk RCSB], [https://www.ebi.ac.uk/pdbsum/24nk PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=24nk ProSAT]</span></td></tr>
</table>
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
Bioluminescence occurs in marine organisms and involves the oxidation of imidazopyrazinone-type luciferin catalyzed by luciferase. Although chemiluminescence mechanisms have been studied using luciferin analogs in aprotic solvents, the enzymatic reaction within luciferase remains poorly understood due to the lack of structural information. Cypridina luciferin (CypL), used by Vargula hilgendorfii, is an imidazopyrazinone compound known for its high quantum yield and turnover rate. Here, we report the crystal structure of Cypridina luciferase (CLuc) and its reaction product, Cypridina oxyluciferin (CypOL). Structural analysis and mutagenesis suggest that the amino acid residue H542 may mediate either deprotonation at the N7 position or stabilization of the anionic form of CypL in the first step of the oxidation process. This mechanism, together with strict substrate recognition, would provide a clue to investigate the molecular basis of CLuc's efficient light emission and advance understanding of imidazopyrazinone-type bioluminescence.

Three-dimensional structure of Cypridina luciferase illuminates the mechanism of bioluminescence of imidazopyrazinone-type luciferin.,Kihira K, Yasuno R, Kanie S, Wu C, Mitani Y, Ohmiya Y Int J Biol Macromol. 2026 Mar 20;357:151583. doi: 10.1016/j.ijbiomac.2026.151583. PMID:41865923<ref>PMID:41865923</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 24nk" style="background-color:#fffaf0;"></div>
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Cypridina noctiluca]]
[[Category: Large Structures]]
[[Category: Kanie S]]
[[Category: Kihira K]]
[[Category: Mitani Y]]
[[Category: Ohmiya Y]]
[[Category: Wu C]]
[[Category: Yasuno R]]