View source for 7na0


==Structure of Geobacter sulfurreducens proline utilization A (PutA) variant A206W==
<StructureSection load='7na0' size='340' side='right'caption='[[7na0]], [[Resolution|resolution]] 1.90&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[7na0]] is a 2 chain structure with sequence from [https://en.wikipedia.org/wiki/Geobacter_sulfurreducens_PCA Geobacter sulfurreducens PCA]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=7NA0 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=7NA0 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]] 1.9&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=EDO:1,2-ETHANEDIOL'>EDO</scene>, <scene name='pdbligand=FAD:FLAVIN-ADENINE+DINUCLEOTIDE'>FAD</scene>, <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=7na0 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=7na0 OCA], [https://pdbe.org/7na0 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=7na0 RCSB], [https://www.ebi.ac.uk/pdbsum/7na0 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=7na0 ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/Q746X3_GEOSL Q746X3_GEOSL] 
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
In many bacteria, the reactions of proline catabolism are catalyzed by the bifunctional enzyme known as proline utilization A (PutA). PutA catalyzes the two-step oxidation of l-proline to l-glutamate using distinct proline dehydrogenase (PRODH) and l-glutamate-gamma-semialdehyde dehydrogenase (GSALDH) active sites, which are separated by over 40 A and connected by a complex tunnel system. The tunnel system consists of a main tunnel that connects the two active sites and functions in substrate channeling, plus six ancillary tunnels whose functions are unknown. Here we used tunnel-blocking mutagenesis to probe the role of a dynamic ancillary tunnel (tunnel 2a) whose shape is modulated by ligand binding to the PRODH active site. The 1.90 A resolution crystal structure of Geobacter sulfurreducens PutA variant A206W verified that the side chain of Trp206 cleanly blocks tunnel 2a without perturbing the surrounding structure. Steady-state kinetic measurements indicate the mutation impaired PRODH activity without affecting the GSALDH activity. Single-turnover experiments corroborated a severe impairment of PRODH activity with flavin reduction decreased by nearly 600-fold in A206W relative to wild-type. Substrate channeling is also significantly impacted as A206W exhibited a 3000-fold lower catalytic efficiency in coupled PRODH-GSALDH activity assays, which measure NADH formation as a function of proline. The structure suggests that Trp206 inhibits binding of the substrate l-proline by preventing the formation of a conserved glutamate-arginine ion pair and closure of the PRODH active site. Our data are consistent with tunnel 2a serving as an open space through which the glutamate of the ion pair travels during the opening and closing of the active site in response to binding l-proline. These results confirm the essentiality of the conserved ion pair in binding l-proline and support the hypothesis that the ion pair functions as a gate that controls access to the PRODH active site.

Probing the function of a ligand-modulated dynamic tunnel in bifunctional proline utilization A (PutA).,Korasick DA, Christgen SL, Qureshi IA, Becker DF, Tanner JJ Arch Biochem Biophys. 2021 Sep 15;712:109025. doi: 10.1016/j.abb.2021.109025. PMID:34506758<ref>PMID:34506758</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 7na0" style="background-color:#fffaf0;"></div>

==See Also==
*[[Proline utilization A|Proline utilization A]]
== References ==
<references/>
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</StructureSection>
[[Category: Geobacter sulfurreducens PCA]]
[[Category: Large Structures]]
[[Category: Korasick DA]]
[[Category: Tanner JJ]]