1i75: Difference between revisions

[[Image:1i75.jpg|left|200px]]<br /><applet load="1i75" size="350" color="white" frame="true" align="right" spinBox="true"  

1-Deoxynojirimycin, a pseudo-monosaccharide, is a strong inhibitor of glucoamylase but a relatively weak inhibitor of cyclodextrin glucanotransferase (CGTase). To elucidate this difference, the crystal structure of the CGTase from alkalophilic Bacillus sp. 1011 complexed with 1-deoxynojirimycin was determined at 2.0 A resolution with the crystallographic R value of 0.154 (R(free) = 0.214). The asymmetric unit of the crystal contains two CGTase molecules and each molecule binds two 1-deoxynojirimycins. One 1-deoxynojirimycin molecule is bound to the active center by hydrogen bonds with catalytic residues and water molecules, but its binding mode differs from that expected in the substrate binding. Another 1-deoxynojirimycin found at the maltose-binding site 1 is bound to Asn-667 with a hydrogen bond and by stacking interaction with the indole moiety of Trp-662 of molecule 1 or Trp-616 of molecule 2. Comparison of this structure with that of the acarbose-CGTase complex suggested that the lack of stacking interaction with the aromatic side chain of Tyr-100 is responsible for the weak inhibition by 1-deoxynojirimycin of the enzymatic action of CGTase.

1I75 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Bacillus_sp. Bacillus sp.] with <scene name='pdbligand=CA:'>CA</scene> and <scene name='pdbligand=NOJ:'>NOJ</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/Cyclomaltodextrin_glucanotransferase Cyclomaltodextrin glucanotransferase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=2.4.1.19 2.4.1.19] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1I75 OCA].  

Crystal structure of cyclodextrin glucanotransferase from alkalophilic Bacillus sp. 1011 complexed with 1-deoxynojirimycin at 2.0 A resolution., Kanai R, Haga K, Yamane K, Harata K, J Biochem. 2001 Apr;129(4):593-8. PMID:[http://ispc.weizmann.ac.il//pmbin/getpm?pmid=11275559 11275559]

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