1gim

<table><tr><td colspan='2'>[[1gim]] is a 1 chain structure with sequence from [http://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1GIM OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1GIM FirstGlance]. <br>

</td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat"><scene name='pdbligand=GDP:GUANOSINE-5-DIPHOSPHATE'>GDP</scene>, <scene name='pdbligand=HDA:HADACIDIN'>HDA</scene>, <scene name='pdbligand=IMP:INOSINIC+ACID'>IMP</scene>, <scene name='pdbligand=MG:MAGNESIUM+ION'>MG</scene>, <scene name='pdbligand=NO3:NITRATE+ION'>NO3</scene></td></tr>

<tr id='activity'><td class="sblockLbl"><b>Activity:</b></td><td class="sblockDat"><span class='plainlinks'>[http://en.wikipedia.org/wiki/Adenylosuccinate_synthase Adenylosuccinate synthase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=6.3.4.4 6.3.4.4] </span></td></tr>

<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1gim FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1gim OCA], [http://pdbe.org/1gim PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=1gim RCSB], [http://www.ebi.ac.uk/pdbsum/1gim PDBsum], [http://prosat.h-its.org/prosat/prosatexe?pdbcode=1gim ProSAT]</span></td></tr>

[[http://www.uniprot.org/uniprot/PURA_ECOLI PURA_ECOLI]] Plays an important role in the de novo pathway of purine nucleotide biosynthesis. Catalyzes the first committed step in the biosynthesis of AMP from IMP (By similarity).[HAMAP-Rule:MF_00011]

<div style="background-color:#fffaf0;">

== Publication Abstract from PubMed ==

Crystal structures of adenylosuccinate synthetase from Esherichia coli complexed with Mg2+, IMP, GDP, NO3- and hadacidin at 298 and 100 K have been refined to R-factors of 0.188 and 0.206 against data to 2.8 A and 2.5 A resolution, respectively. Conformational changes of up to 9 A relative to the unligated enzyme occur in loops that bind to Mg2+, GDP, IMP and hadacidin. Mg2+ binds directly to GDP, NO3-, hadacidin and the protein, but is only five-coordinated. Asp13, which approaches, but does not occupy the sixth coordination site of Mg2+, hydrogen bonds to N1 of IMP. The nitrogen atom of NO3- is approximately 2.7 A from O6 of IMP, reflecting a strong electrostatic interaction between the electron-deficient nitrogen atom and the electron-rich O6. The spatial relationships between GDP, NO3- and Mg2+ suggest an interaction between the beta,gamma-bridging oxygen atom of GTP and Mg2+ in the enzyme-substrate complex. His41 hydrogen bonds to the beta-phosphate group of GDP and approaches bound NO3-. The aldehyde group of hadacidin coordinates to the Mg2+, while its carboxyl group interacts with backbone amide groups 299 to 303 and the side-chain of Arg303. The 5'-phosphate group of IMP interacts with Asn38, Thr129, Thr239 and Arg143 (from a monomer related by 2-fold symmetry). A mechanism is proposed for the two-step reaction governed by the synthetase, in which His41 and Asp13 are essential catalytic side-chains.

Crystal structures of adenylosuccinate synthetase from Escherichia coli complexed with GDP, IMP hadacidin, NO3-, and Mg2+.,Poland BW, Fromm HJ, Honzatko RB J Mol Biol. 1996 Dec 20;264(5):1013-27. PMID:9000627<ref>PMID:9000627</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>

</div>

<div class="pdbe-citations 1gim" style="background-color:#fffaf0;"></div>

== References ==

<references/>

[[Category: Adenylosuccinate synthase]]

[[Category: Fromm, H J]]

[[Category: Honzatko, R B]]

[[Category: Poland, B W]]

[[Category: Synthetase]]