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| [[Image:2bhu.gif|left|200px]] | | {{Seed}} |
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| {{STRUCTURE_2bhu| PDB=2bhu | SCENE= }} | | {{STRUCTURE_2bhu| PDB=2bhu | SCENE= }} |
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| '''CRYSTAL STRUCTURE OF DEINOCOCCUS RADIODURANS MALTOOLIGOSYLTREHALOSE TREHALOHYDROLASE'''
| | ===CRYSTAL STRUCTURE OF DEINOCOCCUS RADIODURANS MALTOOLIGOSYLTREHALOSE TREHALOHYDROLASE=== |
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| ==Overview==
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| Trehalose (alpha-D-glucopyranosyl-1,1-alpha-D-glucopyranose) is a non-reducing diglucoside found in various organisms that serves as a carbohydrate reserve and as an agent that protects against a variety of physical and chemical stresses. Deinococcus radiodurans possesses an alternative biosynthesis pathway for the synthesis of trehalose from maltooligosaccharides. This reaction is mediated by two enzymes: maltooligosyltrehalose synthase (MTSase) and maltooligosyltrehalose trehalohydrolase (MTHase). Here, we present the 1.1A resolution crystal structure of MTHase. It consists of three major domains: two beta-sheet domains and a conserved glycosidase (beta/alpha)8 barrel catalytic domain. Three subdomains consisting of short insertions were identified within the catalytic domain. Subsequently, structures of MTHase in complex with maltose and trehalose were obtained at 1.2 A and 1.5 A resolution, respectively. These structures reveal the importance of the three inserted subdomains in providing the key residues required for substrate recognition. Trehalose is recognised specifically in the +1 and +2 binding subsites by an extensive hydrogen-bonding network and a strong hydrophobic stacking interaction in between two aromatic residues. Moreover, upon binding to maltose, which mimics the substrate sugar chain, a major concerted conformational change traps the sugar chain in the active site. The presence of magnesium in the active site of the MTHase-maltose complex suggests that MTHase activity may be regulated by divalent cations.
| | The line below this paragraph, {{ABSTRACT_PUBMED_15784255}}, adds the Publication Abstract to the page |
| | (as it appears on PubMed at http://www.pubmed.gov), where 15784255 is the PubMed ID number. |
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| | {{ABSTRACT_PUBMED_15784255}} |
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| ==About this Structure== | | ==About this Structure== |
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| [[Category: Protein-carbohydrate complex]] | | [[Category: Protein-carbohydrate complex]] |
| [[Category: Trehalose]] | | [[Category: Trehalose]] |
| ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sat May 3 20:18:33 2008'' | | |
| | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sun Jul 27 23:14:54 2008'' |
