1bf2
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(New page: 200px<br /><applet load="1bf2" size="450" color="white" frame="true" align="right" spinBox="true" caption="1bf2, resolution 2.0Å" /> '''STRUCTURE OF PSEUDOMO...)
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Revision as of 09:28, 20 November 2007
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STRUCTURE OF PSEUDOMONAS ISOAMYLASE
Overview
The three-dimensional structure of isoamylase from Pseudomonas, amyloderamosa, which hydrolyzes alpha-1,6-glucosidic linkages of, amylopectin and glycogen, has been determined by X-ray structure analysis., The enzyme has 750 amino acid residues and a molecular mass of 80 kDa, and, it can be crystallized from ammonium sulfate solution. The structure was, elucidated by the multiple isomorphous replacement method and refined at, 2.2 A resolution, resulting in a final R-factor of 0.161 for significant, reflections with a root-mean-square deviation from ideality in bond, lengths of 0.009 A. The analysis revealed that in the N-terminal region, isoamylase has a novel extra domain that we call domain N, whose, three-dimensional structure has not so far been reported. It has a, (beta/alpha)8-barrel-type supersecondary structure in the catalytic domain, common to the alpha-amylase family enzymes, though the barrel is, incomplete, with a deletion of an alpha-helix between the fifth and sixth, beta-strands. A long excursed region is present between the third, beta-strand and the third alpha-helix of the barrel but, in contrast to, the so-called domain B that has been identified in the other enzymes of, alpha-amylase family, it cannot be considered to be an independent domain, because this loop forms a globular cluster together with the loop between, the fourth beta-strand and the fourth alpha-helix. Isoamylase contains a, bound calcium ion, but this is not in the same position as the conserved, calcium ion that has been reported in other alpha-amylase family enzymes.
About this Structure
1BF2 is a Single protein structure of sequence from Pseudomonas amyloderamosa with CA as ligand. Active as Isoamylase, with EC number 3.2.1.68 Full crystallographic information is available from OCA.
Reference
Three-dimensional structure of Pseudomonas isoamylase at 2.2 A resolution., Katsuya Y, Mezaki Y, Kubota M, Matsuura Y, J Mol Biol. 1998 Sep 4;281(5):885-97. PMID:9719642
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