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1smd

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[[Image:1smd.gif|left|200px]]<br /><applet load="1smd" size="350" color="white" frame="true" align="right" spinBox="true"
 
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caption="1smd, resolution 1.6&Aring;" />
 
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'''HUMAN SALIVARY AMYLASE'''<br />
 
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==Overview==
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==HUMAN SALIVARY AMYLASE==
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Salivary alpha-amylase, a major component of human saliva, plays a role in the initial digestion of starch and may be involved in the colonization of bacteria involved in early dental plaque formation. The three-dimensional atomic structure of salivary amylase has been determined to understand the structure-function relationships of this enzyme. This structure was refined to an R value of 18.4% with 496 amino-acid residues, one calcium ion, one chloride ion and 170 water molecules. Salivary amylase folds into a multidomain structure consisting of three domains, A, B and C. Domain A has a (beta/alpha)(8-) barrel structure, domain B has no definite topology and domain C has a Greek-key barrel structure. The Ca(2+) ion is bound to Asnl00, Arg158, Asp167, His201 and three water molecules. The Cl(-) ion is bound to Arg195, Asn298 and Arg337 and one water molecule. The highly mobile glycine-rich loop 304-310 may act as a gateway for substrate binding and be involved in a 'trap-release' mechanism in the hydrolysis of substrates. Strategic placement of calcium and chloride ions, as well as histidine and tryptophan residues may play a role in differentiating between the glycone and aglycone ends of the polysaccharide substrates. Salivary amylase also possesses a suitable site for binding to enamel surfaces and provides potential sites for the binding of bacterial adhesins.
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<StructureSection load='1smd' size='340' side='right'caption='[[1smd]], [[Resolution|resolution]] 1.60&Aring;' scene=''>
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== Structural highlights ==
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<table><tr><td colspan='2'>[[1smd]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens]. The February 2006 RCSB PDB [https://pdb.rcsb.org/pdb/static.do?p=education_discussion/molecule_of_the_month/index.html Molecule of the Month] feature on ''Alpha-amylase'' by David S. Goodsell is [https://dx.doi.org/10.2210/rcsb_pdb/mom_2006_2 10.2210/rcsb_pdb/mom_2006_2]. The June 2011 RCSB PDB [https://pdb.rcsb.org/pdb/static.do?p=education_discussion/molecule_of_the_month/index.html Molecule of the Month] feature on ''Glucansucrase'' by David Goodsell is [https://dx.doi.org/10.2210/rcsb_pdb/mom_2011_6 10.2210/rcsb_pdb/mom_2011_6]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1SMD OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1SMD FirstGlance]. <br>
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</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">X-ray diffraction, [[Resolution|Resolution]] 1.6&#8491;</td></tr>
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<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=CA:CALCIUM+ION'>CA</scene>, <scene name='pdbligand=CL:CHLORIDE+ION'>CL</scene>, <scene name='pdbligand=PCA:PYROGLUTAMIC+ACID'>PCA</scene></td></tr>
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<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=1smd FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1smd OCA], [https://pdbe.org/1smd PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1smd RCSB], [https://www.ebi.ac.uk/pdbsum/1smd PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1smd ProSAT]</span></td></tr>
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</table>
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== Function ==
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[https://www.uniprot.org/uniprot/AMY1A_HUMAN AMY1A_HUMAN] Calcium-binding enzyme that initiates starch digestion in the oral cavity (PubMed:12527308). Catalyzes the hydrolysis of internal (1->4)-alpha-D-glucosidic bonds, yielding a mixture of maltose, isomaltose, small amounts of glucose as well as small linear and branched oligosaccharides called dextrins (PubMed:12527308).<ref>PMID:12527308</ref>
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== Evolutionary Conservation ==
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[[Image:Consurf_key_small.gif|200px|right]]
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Check<jmol>
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<jmolCheckbox>
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<scriptWhenChecked>; select protein; define ~consurf_to_do selected; consurf_initial_scene = true; script "/wiki/ConSurf/sm/1smd_consurf.spt"</scriptWhenChecked>
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<scriptWhenUnchecked>script /wiki/extensions/Proteopedia/spt/initialview01.spt</scriptWhenUnchecked>
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<text>to colour the structure by Evolutionary Conservation</text>
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</jmolCheckbox>
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</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=1smd ConSurf].
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<div style="clear:both"></div>
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==About this Structure==
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==See Also==
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1SMD is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens] with <scene name='pdbligand=CA:'>CA</scene> and <scene name='pdbligand=CL:'>CL</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. The following page contains interesting information on the relation of 1SMD with [[http://pdb.rcsb.org/pdb/static.do?p=education_discussion/molecule_of_the_month/pdb74_1.html Alpha-amylase]]. Active as [http://en.wikipedia.org/wiki/Alpha-amylase Alpha-amylase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.2.1.1 3.2.1.1] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1SMD OCA].
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*[[Amylase 3D structures|Amylase 3D structures]]
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== References ==
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==Reference==
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<references/>
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Structure of human salivary alpha-amylase at 1.6 A resolution: implications for its role in the oral cavity., Ramasubbu N, Paloth V, Luo Y, Brayer GD, Levine MJ, Acta Crystallogr D Biol Crystallogr. 1996 May 1;52(Pt 3):435-46. PMID:[http://ispc.weizmann.ac.il//pmbin/getpm?pmid=15299664 15299664]
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__TOC__
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</StructureSection>
[[Category: Alpha-amylase]]
[[Category: Alpha-amylase]]
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[[Category: Glucansucrase]]
[[Category: Homo sapiens]]
[[Category: Homo sapiens]]
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[[Category: Single protein]]
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[[Category: Large Structures]]
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[[Category: Ramasubbu, N.]]
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[[Category: RCSB PDB Molecule of the Month]]
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[[Category: CA]]
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[[Category: Ramasubbu N]]
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[[Category: CL]]
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[[Category: carbohydrate metabolism]]
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[[Category: hydrolase]]
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[[Category: o-glycosyl]]
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''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 15:02:58 2008''
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HUMAN SALIVARY AMYLASE

PDB ID 1smd

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