1up4: Difference between revisions

Revision as of 16:27, 21 February 2008

STRUCTURE OF THE 6-PHOSPHO-BETA GLUCOSIDASE FROM THERMOTOGA MARITIMA AT 2.85 ANSTROM RESOLUTION IN THE MONOCLINIC FORM

OverviewOverview

The import of disaccharides by many bacteria is achieved through their simultaneous translocation and phosphorylation by the phosphoenolpyruvate-dependent phosphotransferase system (PEP-PTS). The imported phospho-disaccharides are, in some cases, subsequently hydrolyzed by members of the unusual glycoside hydrolase family GH4. The GH4 enzymes, occasionally found also in bacteria such as Thermotoga maritima that do not utilise a PEP-PTS system, require both NAD(+) and Mn(2+) for catalysis. A further curiosity of this family is that closely related enzymes may show specificity for either alpha-d- or beta-d-glycosides. Here, we present, for the first time, the three-dimensional structure (using single-wavelength anomalous dispersion methods, harnessing extensive non-crystallographic symmetry) of the 6-phospho-beta-glycosidase, BglT, from T.maritima in native and complexed (NAD(+) and Glc6P) forms. Comparison of the active-center structure with that of the 6-phospho-alpha-glucosidase GlvA from Bacillus subtilis reveals a striking degree of structural similarity that, in light of previous kinetic isotope effect data, allows the postulation of a common reaction mechanism for both alpha and beta-glycosidases. Given that the "chemistry" occurs primarily on the glycone sugar and features no nucleophilic attack on the intact disaccharide substrate, modulation of anomeric specificity for alpha and beta-linkages is accommodated through comparatively minor structural changes.

About this StructureAbout this Structure

1UP4 is a Single protein structure of sequence from Thermotoga maritima. Active as Endo-1,3(4)-beta-glucanase, with EC number 3.2.1.6 Full crystallographic information is available from OCA.

ReferenceReference

NAD+ and metal-ion dependent hydrolysis by family 4 glycosidases: structural insight into specificity for phospho-beta-D-glucosides., Varrot A, Yip VL, Li Y, Rajan SS, Yang X, Anderson WF, Thompson J, Withers SG, Davies GJ, J Mol Biol. 2005 Feb 18;346(2):423-35. Epub 2005 Jan 7. PMID:15670594

Page seeded by OCA on Thu Feb 21 15:26:54 2008

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-[[Image:1up4.jpg|left|200px]]<br /><applet load="1up4" size="450" color="white" frame="true" align="right" spinBox="true"
+[[Image:1up4.jpg|left|200px]]<br /><applet load="1up4" size="350" color="white" frame="true" align="right" spinBox="true"
 caption="1up4, resolution 2.85&Aring;" />
 '''STRUCTURE OF THE 6-PHOSPHO-BETA GLUCOSIDASE FROM THERMOTOGA MARITIMA AT 2.85 ANSTROM RESOLUTION IN THE MONOCLINIC FORM'''<br />
 ==Overview==
-The import of disaccharides by many bacteria is achieved through their, simultaneous translocation and phosphorylation by the, phosphoenolpyruvate-dependent phosphotransferase system (PEP-PTS). The, imported phospho-disaccharides are, in some cases, subsequently hydrolyzed, by members of the unusual glycoside hydrolase family GH4. The GH4 enzymes, occasionally found also in bacteria such as Thermotoga maritima that do, not utilise a PEP-PTS system, require both NAD(+) and Mn(2+) for, catalysis. A further curiosity of this family is that closely related, enzymes may show specificity for either alpha-d- or beta-d-glycosides., Here, we present, for the first time, the three-dimensional structure, (using single-wavelength anomalous dispersion methods, harnessing, extensive non-crystallographic symmetry) of the, 6-phospho-beta-glycosidase, BglT, from T.maritima in native and complexed, (NAD(+) and Glc6P) forms. Comparison of the active-center structure with, that of the 6-phospho-alpha-glucosidase GlvA from Bacillus subtilis, reveals a striking degree of structural similarity that, in light of, previous kinetic isotope effect data, allows the postulation of a common, reaction mechanism for both alpha and beta-glycosidases. Given that the, "chemistry" occurs primarily on the glycone sugar and features no, nucleophilic attack on the intact disaccharide substrate, modulation of, anomeric specificity for alpha and beta-linkages is accommodated through, comparatively minor structural changes.
+The import of disaccharides by many bacteria is achieved through their simultaneous translocation and phosphorylation by the phosphoenolpyruvate-dependent phosphotransferase system (PEP-PTS). The imported phospho-disaccharides are, in some cases, subsequently hydrolyzed by members of the unusual glycoside hydrolase family GH4. The GH4 enzymes, occasionally found also in bacteria such as Thermotoga maritima that do not utilise a PEP-PTS system, require both NAD(+) and Mn(2+) for catalysis. A further curiosity of this family is that closely related enzymes may show specificity for either alpha-d- or beta-d-glycosides. Here, we present, for the first time, the three-dimensional structure (using single-wavelength anomalous dispersion methods, harnessing extensive non-crystallographic symmetry) of the 6-phospho-beta-glycosidase, BglT, from T.maritima in native and complexed (NAD(+) and Glc6P) forms. Comparison of the active-center structure with that of the 6-phospho-alpha-glucosidase GlvA from Bacillus subtilis reveals a striking degree of structural similarity that, in light of previous kinetic isotope effect data, allows the postulation of a common reaction mechanism for both alpha and beta-glycosidases. Given that the "chemistry" occurs primarily on the glycone sugar and features no nucleophilic attack on the intact disaccharide substrate, modulation of anomeric specificity for alpha and beta-linkages is accommodated through comparatively minor structural changes.
 ==About this Structure==
-UP4 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Thermotoga_maritima Thermotoga maritima]. Active as [http://en.wikipedia.org/wiki/Endo-1,3(4)-beta-glucanase Endo-1,3(4)-beta-glucanase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.2.1.6 3.2.1.6] Full crystallographic information is available from [http://ispc.weizmann.ac.il/oca-bin/ocashort?id=1UP4 OCA].
+UP4 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Thermotoga_maritima Thermotoga maritima]. Active as [http://en.wikipedia.org/wiki/Endo-1,3(4)-beta-glucanase Endo-1,3(4)-beta-glucanase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.2.1.6 3.2.1.6] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1UP4 OCA].
 ==Reference==
@@ Line 14: / Line 14: @@
 [[Category: Single protein]]
 [[Category: Thermotoga maritima]]
-[[Category: Davies, G.J.]]
+[[Category: Davies, G J.]]
 [[Category: Varrot, A.]]
-[[Category: Withers, S.G.]]
+[[Category: Withers, S G.]]
-[[Category: Yip, V.L.]]
+[[Category: Yip, V L.]]
 [[Category: 6-phospho-beta-glucosidase]]
 [[Category: family4 hydrolase]]
 [[Category: nad-dependent]]
-''Page seeded by [http://ispc.weizmann.ac.il/oca OCA ] on Wed Nov 21 04:17:03 2007''
+''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 15:26:54 2008''