==Tris/maltotriose complex of chimaeric amylase from B. amyloliquefaciens and B. licheniformis at 2.2A==

<StructureSection load='1e40' size='340' side='right'caption='[[1e40]], [[Resolution|resolution]] 2.20&Aring;' scene=''>

<table><tr><td colspan='2'>[[1e40]] is a 1 chain structure with sequence from [http://en.wikipedia.org/wiki/"bacillus_amyloliquifaciens"_(sic)_fukumoto_1943 "bacillus amyloliquifaciens" (sic) fukumoto 1943]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1E40 OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1E40 FirstGlance]. <br>

</td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat"><scene name='pdbligand=CA:CALCIUM+ION'>CA</scene>, <scene name='pdbligand=GLC:ALPHA-D-GLUCOSE'>GLC</scene>, <scene name='pdbligand=NA:SODIUM+ION'>NA</scene>, <scene name='pdbligand=TRS:2-AMINO-2-HYDROXYMETHYL-PROPANE-1,3-DIOL'>TRS</scene></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=1e40 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1e40 OCA], [http://pdbe.org/1e40 PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=1e40 RCSB], [http://www.ebi.ac.uk/pdbsum/1e40 PDBsum], [http://prosat.h-its.org/prosat/prosatexe?pdbcode=1e40 ProSAT]</span></td></tr>

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== Publication Abstract from PubMed ==

Several chimeric alpha-amylases genes were constructed by an in vivo recombination technique from the Bacillus amyloliquefaciens and Bacillus licheniformis genes. One of the fusion amylases (hereafter BA2), consisting of residues 1-300 from B. amyloliquefaciens and 301-483 from B. licheniformis, has been extensively studied by X-ray crystallography at resolutions between 2.2 and 1.7 A. The 3-dimensional structure of the native enzyme was solved by multiple isomorphous replacement, and refined at a resolution of 1.7 A. It consists of 483 amino acids, organized similarly to the known B. lichiniformis alpha-amylase structure [Machius et al. (1995) J. Mol. Biol. 246, 545-559], but features 4 bound calcium ions. Two of these form part of a linear cluster of three ions, the central ion being attributed to sodium. This cluster lies at the junction of the A and B domains with one calcium of the cluster structurally equivalent to the major Ca(2+) binding site of fungal alpha-amylases. The third calcium ion is found at the interface of the A and C domains. BA2 contains a fourth calcium site, not observed in the B. licheniformis alpha-amylase structure. It is found on the C domain where it bridges the two beta-sheets. Three acid residues (Glu261, Asp328, and Asp231) form an active site similar to that seen in other amylases. In the presence of TRIS buffer, a single molecule of TRIS occupies the -1 subsite of the enzyme where it is coordinated by the three active-center carboxylates. Kinetic data reveal that BA2 displays properties intermediate to those of its parents. Data for crystals soaked in maltooligosaccharides reveal the presence of a maltotriose binding site on the N-terminal face of the (beta/alpha)(8) barrel of the molecule, not previously described for any alpha-amylase structure, the biological function of which is unclear. Data for a complex soaked with the tetrasaccharide inhibitor acarbose, at 1.9 A, reveal a decasaccharide moiety, spanning the -7 to +3 subsites of the enzyme. The unambiguous presence of three unsaturated rings in the (2)H(3) half-chair/(2)E envelope conformation, adjacent to three 6-deoxypyranose units, clearly demonstrates synthesis of this acarbose-derived decasaccharide by a two-step transglycosylation mechanism.

Structural analysis of a chimeric bacterial alpha-amylase. High-resolution analysis of native and ligand complexes.,Brzozowski AM, Lawson DM, Turkenburg JP, Bisgaard-Frantzen H, Svendsen A, Borchert TV, Dauter Z, Wilson KS, Davies GJ Biochemistry. 2000 Aug 8;39(31):9099-107. PMID:10924103<ref>PMID:10924103</ref>

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

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<div class="pdbe-citations 1e40" style="background-color:#fffaf0;"></div>

==See Also==

*[[Amylase 3D structures|Amylase 3D structures]]

== References ==

<references/>

[[Category: Alpha-amylase]]

[[Category: Bisgaard-Frantzen, H]]

[[Category: Dauter, Z]]

[[Category: Tri]]