1val: Difference between revisions

Revision as of 16:33, 21 February 2008

CONCANAVALIN A COMPLEX WITH 4'-NITROPHENYL-ALPHA-D-GLUCOPYRANOSIDE

OverviewOverview

Concanavalin A (Con A) is the best-known plant lectin and has important in vitro biological activities arising from its specific saccharide-binding ability. Its exact biological role still remains unknown. The complexes of Con A with 4'-nitrophenyl-alpha-D-mannopyranoside (alpha-PNM) and 4'-nitrophenyl-alpha-D-glucopyranoside (alpha-PNG) have been crystallized in space group P2(1)2(1)2 with cell dimensions a = 135.19 A, b = 155.38 A, c = 71.25 A and a = 134.66 A, b = 155.67 A, and c = 71.42 A, respectively. X-ray diffraction intensities to 2.75 A for the alpha-PNM and to 3.0 A resolution for the alpha-PNG complex have been collected. The structures of the complexes were solved by molecular replacement and refined by simulated annealing methods to crystallographic R-factor values of 0.185/0.186 and free-R-factor values of 0.260/0.274, respectively. In both structures, the asymmetric unit contains four molecules arranged as a tetramer, with approximate 222 symmetry. A saccharide molecule is bound in the sugar-binding site near the surface of each monomer. The nonsugar (aglycon) portion of the compounds used helps to identify the exact orientation of the saccharide in the sugar-binding pocket and is involved in major interactions between tetramers. The hydrogen bonding network in the region of the binding site has been analyzed, and only minor differences with the previously reported Con A-methyl-alpha-D-mannopyranoside complex structure have been observed. Structural differences that may contribute to the slight preference of the lectin for mannosides over glucosides are discussed. Calculations indicate a negative electrostatic surface potential for the saccharide binding site of Con A, which may be important for its biological activity. It is also shown in detail how a particular class of hydrophobic ligands interact with one of the three so-called characteristic hydrophobic sites of the lectins.

About this StructureAbout this Structure

1VAL is a Single protein structure of sequence from Canavalia ensiformis with , and as ligands. Full crystallographic information is available from OCA.

ReferenceReference

The crystal structure of the complexes of concanavalin A with 4'-nitrophenyl-alpha-D-mannopyranoside and 4'-nitrophenyl-alpha-D-glucopyranoside., Kanellopoulos PN, Pavlou K, Perrakis A, Agianian B, Vorgias CE, Mavrommatis C, Soufi M, Tucker PA, Hamodrakas SJ, J Struct Biol. 1996 May-Jun;116(3):345-55. PMID:8812993

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-[[Image:1val.gif|left|200px]]<br /><applet load="1val" size="450" color="white" frame="true" align="right" spinBox="true"
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 caption="1val, resolution 3.0&Aring;" />
 '''CONCANAVALIN A COMPLEX WITH 4'-NITROPHENYL-ALPHA-D-GLUCOPYRANOSIDE'''<br />
 ==Overview==
-Concanavalin A (Con A) is the best-known plant lectin and has important in, vitro biological activities arising from its specific saccharide-binding, ability. Its exact biological role still remains unknown. The complexes of, Con A with 4'-nitrophenyl-alpha-D-mannopyranoside (alpha-PNM) and, 4'-nitrophenyl-alpha-D-glucopyranoside (alpha-PNG) have been crystallized, in space group P2(1)2(1)2 with cell dimensions a = 135.19 A, b = 155.38 A, c = 71.25 A and a = 134.66 A, b = 155.67 A, and c = 71.42 A, respectively., X-ray diffraction intensities to 2.75 A for the alpha-PNM and to 3.0 A, resolution for the alpha-PNG complex have been collected. The structures, of the complexes were solved by molecular replacement and refined by, simulated annealing methods to crystallographic R-factor values of, 0.185/0.186 and free-R-factor values of 0.260/0.274, respectively. In both, structures, the asymmetric unit contains four molecules arranged as a, tetramer, with approximate 222 symmetry. A saccharide molecule is bound in, the sugar-binding site near the surface of each monomer. The nonsugar, (aglycon) portion of the compounds used helps to identify the exact, orientation of the saccharide in the sugar-binding pocket and is involved, in major interactions between tetramers. The hydrogen bonding network in, the region of the binding site has been analyzed, and only minor, differences with the previously reported Con, A-methyl-alpha-D-mannopyranoside complex structure have been observed., Structural differences that may contribute to the slight preference of the, lectin for mannosides over glucosides are discussed. Calculations indicate, a negative electrostatic surface potential for the saccharide binding site, of Con A, which may be important for its biological activity. It is also, shown in detail how a particular class of hydrophobic ligands interact, with one of the three so-called characteristic hydrophobic sites of the, lectins.
+Concanavalin A (Con A) is the best-known plant lectin and has important in vitro biological activities arising from its specific saccharide-binding ability. Its exact biological role still remains unknown. The complexes of Con A with 4'-nitrophenyl-alpha-D-mannopyranoside (alpha-PNM) and 4'-nitrophenyl-alpha-D-glucopyranoside (alpha-PNG) have been crystallized in space group P2(1)2(1)2 with cell dimensions a = 135.19 A, b = 155.38 A, c = 71.25 A and a = 134.66 A, b = 155.67 A, and c = 71.42 A, respectively. X-ray diffraction intensities to 2.75 A for the alpha-PNM and to 3.0 A resolution for the alpha-PNG complex have been collected. The structures of the complexes were solved by molecular replacement and refined by simulated annealing methods to crystallographic R-factor values of 0.185/0.186 and free-R-factor values of 0.260/0.274, respectively. In both structures, the asymmetric unit contains four molecules arranged as a tetramer, with approximate 222 symmetry. A saccharide molecule is bound in the sugar-binding site near the surface of each monomer. The nonsugar (aglycon) portion of the compounds used helps to identify the exact orientation of the saccharide in the sugar-binding pocket and is involved in major interactions between tetramers. The hydrogen bonding network in the region of the binding site has been analyzed, and only minor differences with the previously reported Con A-methyl-alpha-D-mannopyranoside complex structure have been observed. Structural differences that may contribute to the slight preference of the lectin for mannosides over glucosides are discussed. Calculations indicate a negative electrostatic surface potential for the saccharide binding site of Con A, which may be important for its biological activity. It is also shown in detail how a particular class of hydrophobic ligands interact with one of the three so-called characteristic hydrophobic sites of the lectins.
 ==About this Structure==
-VAL is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Canavalia_ensiformis Canavalia ensiformis] with PNG, MN and CA as [http://en.wikipedia.org/wiki/ligands ligands]. Full crystallographic information is available from [http://ispc.weizmann.ac.il/oca-bin/ocashort?id=1VAL OCA].
+VAL is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Canavalia_ensiformis Canavalia ensiformis] with <scene name='pdbligand=PNG:'>PNG</scene>, <scene name='pdbligand=MN:'>MN</scene> and <scene name='pdbligand=CA:'>CA</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1VAL OCA].
 ==Reference==
@@ Line 13: / Line 13: @@
 [[Category: Canavalia ensiformis]]
 [[Category: Single protein]]
-[[Category: Hamodrakas, S.J.]]
+[[Category: Hamodrakas, S J.]]
-[[Category: Kanellopoulos, P.N.]]
+[[Category: Kanellopoulos, P N.]]
-[[Category: Tucker, P.A.]]
+[[Category: Tucker, P A.]]
 [[Category: CA]]
 [[Category: MN]]
@@ Line 21: / Line 21: @@
 [[Category: legume lectin]]
-''Page seeded by [http://ispc.weizmann.ac.il/oca OCA ] on Wed Nov 21 04:33:16 2007''
+''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 15:33:16 2008''