1fhl: Difference between revisions

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

The three-dimensional structure of Aspergillus aculeatus beta-1,4-galactanase (AAGAL), an enzyme involved in pectin degradation, has been determined by multiple isomorphous replacement to 2.3 and 1.8 A resolution at 293 and 100 K, respectively. It represents the first known structure for a polysaccharidase with this specificity and for a member of glycoside hydrolase family 53 (GH-53). The enzyme folds into a (beta/alpha)(8) barrel with the active site cleft located at the C-terminal side of the barrel consistent with the classification of GH-53 in clan GH-A, a superfamily of enzymes with common fold and catalytic machinery but diverse specificities. Putative substrate-enzyme interactions were elucidated by modeling of beta-1,4-linked galactobioses into the possible substrate binding subsites. The structure and modeling studies identified five potential subsites for the binding of galactans, of which one is a pocket suited for accommodating the arabinan side chain in arabinogalactan, one of the natural substrates. A comparison with the substrate binding grooves of other Clan GH-A enzymes suggests that shape complementarity is crucial in determining the specificity of polysaccharidases.

1FHL is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Aspergillus_aculeatus Aspergillus aculeatus]. Active as [http://en.wikipedia.org/wiki/Arabinogalactan_endo-1,4-beta-galactosidase Arabinogalactan endo-1,4-beta-galactosidase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.2.1.89 3.2.1.89] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1FHL OCA].  

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