6czl

<StructureSection load='6czl' size='340' side='right' caption='[[6czl]], [[Resolution|resolution]] 2.92&Aring;' scene=''>

<table><tr><td colspan='2'>[[6czl]] is a 6 chain structure with sequence from [http://en.wikipedia.org/wiki/Barrel_medic Barrel medic]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=6CZL OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=6CZL FirstGlance]. <br>

</td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat"><scene name='pdbligand=CL:CHLORIDE+ION'>CL</scene>, <scene name='pdbligand=GOL:GLYCEROL'>GOL</scene></td></tr>

<tr id='gene'><td class="sblockLbl"><b>[[Gene|Gene:]]</b></td><td class="sblockDat">11438625, MTR_4g130680 ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=3880 Barrel medic])</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=6czl FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=6czl OCA], [http://pdbe.org/6czl PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=6czl RCSB], [http://www.ebi.ac.uk/pdbsum/6czl PDBsum], [http://prosat.h-its.org/prosat/prosatexe?pdbcode=6czl ProSAT]</span></td></tr>

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== Publication Abstract from PubMed ==

In the first committed step of histidine biosynthesis, ATP and 5-phosphoribosyl-alpha1-pyrophosphate (PRPP), in a presence of ATP phosphoribosyltransferase (ATP-PRT, EC 2.4.2.17), yield phosphoribosyl-ATP. ATP-PRTs are subject to feedback inhibition by histidine, that allosterically binds between the regulatory domains. Histidine biosynthetic pathways of bacteria, lower eukaryotes, and plants are considered promising targets for a design of antibiotics, antifungal agents, and herbicides because higher organisms are histidine heterotrophs. Plant ATP-PRTs are similar to one of the two types of their bacterial counterparts, the long-type ATP-PRTs. A biochemical and structural study of ATP-PRT from the model legume plant, Medicago truncatula ( Medtr ATP-PRT1) is reported herein. Two crystal structures, presenting homohexameric Medtr ATP-PRT1 in its relaxed (R-) and histidine-bound, tense (T-) states allowed to observe key features of the enzyme and provided the first structural insights into an ATP-PRT from a eukaryotic organism. In particular, they show pronounced conformational reorganizations during R-state to T-state transition that involves substantial movements of domains. This rearrangement requires a trans - to cis - switch of a peptide backbone within the hinge region of Medtr ATP-PRT1. A C-terminal alpha-helix, absent in bacteria, reinforces the hinge that is constituted by two peptide strands. As a result, conformations of the R- and T-states are significantly different from the corresponding states of prokaryotic enzymes with known 3-D structures. Lastly, AMP bound at the active site is consistent with a competitive (and synergistic with histidine) nature of AMP inhibition.

 

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== References ==

[[Category: Barrel medic]]

[[Category: Ruszkowski, M]]

[[Category: Allosteric regulation]]

[[Category: Transferase]]