1eh9

<table><tr><td colspan='2'>[[1eh9]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/Atcc_35091 Atcc 35091]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1EH9 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1EH9 FirstGlance]. <br>

</td></tr><tr id='related'><td class="sblockLbl"><b>[[Related_structure|Related:]]</b></td><td class="sblockDat"><div style='overflow: auto; max-height: 3em;'>[[1eha|1eha]]</div></td></tr>

<tr id='activity'><td class="sblockLbl"><b>Activity:</b></td><td class="sblockDat"><span class='plainlinks'>[https://en.wikipedia.org/wiki/Alpha-amylase Alpha-amylase], with EC number [https://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.2.1.1 3.2.1.1] </span></td></tr>

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== Publication Abstract from PubMed ==

The crystal structure of glycosyltrehalose trehalohydrolase from the hyperthermophilic archaeum Sulfolobus solfataricus KM1 has been solved by multiple isomorphous replacement. The enzyme is an alpha-amylase (family 13) with unique exo-amylolytic activity for glycosyltrehalosides. It cleaves the alpha-1,4 glycosidic bond adjacent to the trehalose moiety to release trehalose and maltooligo saccharide. Unlike most other family 13 glycosidases, the enzyme does not require Ca(2+) for activity, and it contains an N-terminal extension of approximately 100 amino acid residues that is homologous to N-terminal domains found in many glycosidases that recognize branched oligosaccharides. Crystallography revealed the enzyme to exist as a homodimer covalently linked by an intermolecular disulfide bond at residue C298. The existence of the intermolecular disulfide bond was confirmed by biochemical analysis and mutagenesis. The N-terminal extension forms an independent domain connected to the catalytic domain by an extended linker. The functionally essential Ca(2+) binding site found in the B domain of alpha-amylases and many other family 13 glycosidases was found to be replaced by hydrophobic packing interactions. The enzyme also contains a very unusual excursion in the (beta/alpha)(8) barrel structure of the catalytic domain. This excursion originates from the bottom of the (beta/alpha)(8) barrel between helix 6 and strand 7, but folds upward in a distorted alpha-hairpin structure to form a part of the substrate binding cleft wall that is possibly critical for the enzyme's unique substrate selectivity. Participation of an alpha-beta loop in the formation of the substrate binding cleft is a novel feature that is not observed in other known (beta/alpha)(8) enzymes.

Crystal structure of glycosyltrehalose trehalohydrolase from the hyperthermophilic archaeum Sulfolobus solfataricus.,Feese MD, Kato Y, Tamada T, Kato M, Komeda T, Miura Y, Hirose M, Hondo K, Kobayashi K, Kuroki R J Mol Biol. 2000 Aug 11;301(2):451-64. PMID:10926520<ref>PMID:10926520</ref>

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

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== References ==

<references/>

[[Category: Alpha-amylase]]

[[Category: Atcc 35091]]

[[Category: Feese, M D]]

[[Category: Kato, M]]

[[Category: Kato, Y]]

[[Category: Kobayashi, K]]

[[Category: Komeda, T]]

[[Category: Kuroki, R]]

[[Category: Tamada, T]]

[[Category: Trehalose]]