7mj1: Difference between revisions

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-'''Unreleased structure'''
-The entry 7mj1 is ON HOLD  until Paper Publication
+==LarB, a carboxylase/hydrolase involved in synthesis of the cofactor for lactate racemase, in complex with NAD==
+<StructureSection load='7mj1' size='340' side='right'caption='[[7mj1]], [[Resolution|resolution]] 3.40&Aring;' scene=''>
+== Structural highlights ==
+<table><tr><td colspan='2'>Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=7MJ1 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=7MJ1 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]] 3.402&#8491;</td></tr>
+<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=MG:MAGNESIUM+ION'>MG</scene>, <scene name='pdbligand=NAD:NICOTINAMIDE-ADENINE-DINUCLEOTIDE'>NAD</scene>, <scene name='pdbligand=NAI:1,4-DIHYDRONICOTINAMIDE+ADENINE+DINUCLEOTIDE'>NAI</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=7mj1 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=7mj1 OCA], [https://pdbe.org/7mj1 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=7mj1 RCSB], [https://www.ebi.ac.uk/pdbsum/7mj1 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=7mj1 ProSAT]</span></td></tr>
+</table>
+<div style="background-color:#fffaf0;">
+== Publication Abstract from PubMed ==
+Enzymes possessing the nickel-pincer nucleotide (NPN) cofactor catalyze C2 racemization or epimerization reactions of alpha-hydroxyacid substrates. LarB initiates synthesis of the NPN cofactor from nicotinic acid adenine dinucleotide (NaAD) by performing dual reactions: pyridinium ring C5 carboxylation and phosphoanhydride hydrolysis. Here, we show that LarB uses carbon dioxide, not bicarbonate, as the substrate for carboxylation and activates water for hydrolytic attack on the AMP-associated phosphate of C5-carboxylated-NaAD. Structural investigations show that LarB has an N-terminal domain of unique fold and a C-terminal domain homologous to aminoimidazole ribonucleotide carboxylase/mutase (PurE). Like PurE, LarB is octameric with four active sites located at subunit interfaces. The complex of LarB with NAD(+), an analog of NaAD, reveals the formation of a covalent adduct between the active site Cys221 and C4 of NAD(+), resulting in a boat-shaped dearomatized pyridine ring. The formation of such an intermediate with NaAD would enhance the reactivity of C5 to facilitate carboxylation. Glu180 is well positioned to abstract the C5 proton, restoring aromaticity as Cys221 is expelled. The structure of as-isolated LarB and its complexes with NAD(+) and the product AMP identify additional residues potentially important for substrate binding and catalysis. In combination with these findings, the results from structure-guided mutagenesis studies lead us to propose enzymatic mechanisms for both the carboxylation and hydrolysis reactions of LarB that are distinct from that of PurE.
-Authors: Chatterjee, S., Rankin, J.A., Lagishetty, S., Hu, J., Hausinger, R.P.
+The LarB carboxylase/hydrolase forms a transient cysteinyl-pyridine intermediate during nickel-pincer nucleotide cofactor biosynthesis.,Rankin JA, Chatterjee S, Tariq Z, Lagishetty S, Desguin B, Hu J, Hausinger RP Proc Natl Acad Sci U S A. 2021 Sep 28;118(39). pii: 2106202118. doi:, 10.1073/pnas.2106202118. PMID:34548397<ref>PMID:34548397</ref>
-Description: LarB, a carboxylase/hydrolase involved in synthesis of the cofactor for lactate racemase, in complex with NAD
+From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
-[[Category: Unreleased Structures]]
+</div>
-[[Category: Lagishetty, S]]
+<div class="pdbe-citations 7mj1" style="background-color:#fffaf0;"></div>
-[[Category: Hausinger, R.P]]
+== References ==
-[[Category: Chatterjee, S]]
+<references/>
-[[Category: Hu, J]]
+__TOC__
-[[Category: Rankin, J.A]]
+</StructureSection>
+[[Category: Large Structures]]
+[[Category: Chatterjee S]]
+[[Category: Hausinger RP]]
+[[Category: Hu J]]
+[[Category: Lagishetty S]]
+[[Category: Rankin JA]]