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| - | [[Image:1mas.jpg|left|200px]] | |
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| - | <!-- | + | ==PURINE NUCLEOSIDE HYDROLASE== |
| - | The line below this paragraph, containing "STRUCTURE_1mas", creates the "Structure Box" on the page.
| + | <StructureSection load='1mas' size='340' side='right'caption='[[1mas]], [[Resolution|resolution]] 2.50Å' scene=''> |
| - | You may change the PDB parameter (which sets the PDB file loaded into the applet)
| + | == Structural highlights == |
| - | or the SCENE parameter (which sets the initial scene displayed when the page is loaded),
| + | <table><tr><td colspan='2'>[[1mas]] is a 2 chain structure with sequence from [https://en.wikipedia.org/wiki/Crithidia_fasciculata Crithidia fasciculata]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1MAS OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1MAS FirstGlance]. <br> |
| - | or leave the SCENE parameter empty for the default display.
| + | </td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">X-ray diffraction, [[Resolution|Resolution]] 2.5Å</td></tr> |
| - | -->
| + | <tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=K:POTASSIUM+ION'>K</scene></td></tr> |
| - | {{STRUCTURE_1mas| PDB=1mas | SCENE= }}
| + | <tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=1mas FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1mas OCA], [https://pdbe.org/1mas PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1mas RCSB], [https://www.ebi.ac.uk/pdbsum/1mas PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1mas ProSAT]</span></td></tr> |
| - | | + | </table> |
| - | '''PURINE NUCLEOSIDE HYDROLASE''' | + | == Function == |
| - | | + | [https://www.uniprot.org/uniprot/IUNH_CRIFA IUNH_CRIFA] Catalyzes the hydrolysis of all of the commonly occurring purine and pyrimidine nucleosides into ribose and the associated base, but has a preference for inosine and uridine as substrates. |
| - | | + | == Evolutionary Conservation == |
| - | ==Overview== | + | [[Image:Consurf_key_small.gif|200px|right]] |
| - | Protozoan parasites rely on the host for purines since they lack a de novo synthetic pathway. Crithidia fasciculata salvages exogenous inosine primarily through hydrolysis of the N-ribosidic bond using several nucleoside hydrolases. The most abundant nucleoside hydrolase is relatively nonspecific but prefers inosine and uridine as substrates. Here we report the three-dimensional structure of the inosine-uridine nucleoside hydrolase (IU-NH) from C. fasciculata determined by X-ray crystallography at a nominal resolution of 2.5 A. The enzyme has an open (alpha, beta) structure which differs from the classical dinucleotide binding fold. IU-nucleoside hydrolase is composed of a mixed eight-stranded beta sheet surrounded by six alpha helices and a small C-terminal lobe composed of four alpha helices. Two short antiparallel beta strands are involved in intermolecular contacts. The catalytic pocket is located at the C-terminal end of beta strands beta 1 and beta 4. Four aspartate residues are located at the bottom of the cavity in a geometry which suggests interaction with the ribose moiety of the nucleoside. These groups could provide the catalytically important interactions to the ribosyl hydroxyls and the stabilizing anion for the oxycarbonium-like transition state. Histidine 241, located on the side of the active site cavity, is the proposed proton donor which facilitates purine base departure [Gopaul, D. N., Meyer, S. L., Degano, M., Sacchettini, J. C., & Schramm, V. L. (1996) Biochemistry 35, 5963-5970]. The substrate binding site is unlike that from purine nucleoside phosphorylase, phosphoribosyltransferases, or uracil DNA glycosylase and thus represents a novel architecture for general acid-base catalysis. This detailed knowledge of the architecture of the active site, together with the previous transition state analysis [Horenstein, B. A., Parkin, D. W., Estupinan, B., & Schramm, V. L. (1991) Biochemistry 30, 10788-10795], allows analysis of the interactions leading to catalysis and an explanation for the tight-binding inhibitors of the enzyme [Schramm, V. L., Horenstein, B. A., & Kline, P. C. (1994) J. Biol. Chem. 269, 18259-18262].
| + | Check<jmol> |
| - | | + | <jmolCheckbox> |
| - | ==About this Structure== | + | <scriptWhenChecked>; select protein; define ~consurf_to_do selected; consurf_initial_scene = true; script "/wiki/ConSurf/ma/1mas_consurf.spt"</scriptWhenChecked> |
| - | 1MAS is a [[Single protein]] structure of sequence from [http://en.wikipedia.org/wiki/Crithidia_fasciculata Crithidia fasciculata]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1MAS OCA].
| + | <scriptWhenUnchecked>script /wiki/extensions/Proteopedia/spt/initialview01.spt</scriptWhenUnchecked> |
| - | | + | <text>to colour the structure by Evolutionary Conservation</text> |
| - | ==Reference== | + | </jmolCheckbox> |
| - | Three-dimensional structure of the inosine-uridine nucleoside N-ribohydrolase from Crithidia fasciculata., Degano M, Gopaul DN, Scapin G, Schramm VL, Sacchettini JC, Biochemistry. 1996 May 14;35(19):5971-81. PMID:[http://www.ncbi.nlm.nih.gov/pubmed/8634238 8634238]
| + | </jmol>, as determined by [http://consurfdb.tau.ac.il/ ConSurfDB]. You may read the [[Conservation%2C_Evolutionary|explanation]] of the method and the full data available from [http://bental.tau.ac.il/new_ConSurfDB/main_output.php?pdb_ID=1mas ConSurf]. |
| | + | <div style="clear:both"></div> |
| | + | __TOC__ |
| | + | </StructureSection> |
| | [[Category: Crithidia fasciculata]] | | [[Category: Crithidia fasciculata]] |
| - | [[Category: Purine nucleosidase]] | + | [[Category: Large Structures]] |
| - | [[Category: Single protein]]
| + | [[Category: Degano M]] |
| - | [[Category: Degano, M.]] | + | [[Category: Gopaul DN]] |
| - | [[Category: Gopaul, D N.]] | + | [[Category: Sacchettini JC]] |
| - | [[Category: Sacchettini, J C.]] | + | [[Category: Scapin G]] |
| - | [[Category: Scapin, G.]] | + | [[Category: Schramm VL]] |
| - | [[Category: Schramm, V L.]] | + | |
| - | [[Category: Hydrolase]]
| + | |
| - | [[Category: Iu-nh]]
| + | |
| - | [[Category: Purine nucleosidase]]
| + | |
| - | [[Category: Purine nucleoside hydrolase]]
| + | |
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sat May 3 00:50:06 2008''
| + | |
