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1e4n

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Revision as of 18:30, 25 December 2014

CRYSTAL STRUCTURE OF THE INACTIVE MUTANT MONOCOT (MAIZE ZMGLU1) BETA-GLUCOSIDASE ZMGLU E191D IN COMPLEX WITH THE NATURAL AGLYCONE DIMBOA

Structural highlights

1e4n is a 2 chain structure with sequence from Zea mays. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Ligands:
Related:	1cbg, 1e1e, 1e1f, 1e4l, 1e55, 1e56
Activity:	Beta-glucosidase, with EC number 3.2.1.21
Resources:	FirstGlance, OCA, RCSB, PDBsum

Function

[BGLC_MAIZE] Is implicated in many functions such as ABA metabolism, hydrolysis of conjugated gibberellins, conversion of storage forms of cytokinins to active forms. Also acts in defense of young plant parts against pests via the production of hydroxamic acids from hydroxamic acid glucosides. Enzymatic activity is highly correlated with plant growth. The preferred substrate is DIMBOA-beta-D-glucoside. Hydrolyzes the chromogenic substrate 6-bromo-2-naphthyl-beta-D-glucoside (6BNGlc) and various artificial aryl beta-glucosides. No activity with cellobiose, arbutin, gentiobiose, linamarin or dhurrin as substrates.^[1] ^[2] ^[3]

Evolutionary Conservation

Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf.

Publication Abstract from PubMed

The mechanism and the site of substrate (i.e., aglycone) recognition and specificity were investigated in maize beta-glucosidase (Glu1) by x-ray crystallography by using crystals of a catalytically inactive mutant (Glu1E191D) in complex with the natural substrate 2-O-beta-d-glucopyranosyl-4-hydroxy-7-methoxy-1,4-benzoxazin-3-one (DIMBOAGlc), the free aglycone DIMBOA, and competitive inhibitor para-hydroxy-S-mandelonitrile beta-glucoside (dhurrin). The structures of these complexes and of the free enzyme were solved at 2.1-, 2.1-, 2.0-, and 2.2-A resolution, respectively. The structural data from the complexes allowed us to visualize an intact substrate, free aglycone, or a competitive inhibitor in the slot-like active site of a beta-glucosidase. These data show that the aglycone moiety of the substrate is sandwiched between W378 on one side and F198, F205, and F466 on the other. Thus, specific conformations of these four hydrophobic amino acids and the shape of the aglycone-binding site they form determine aglycone recognition and substrate specificity in Glu1. In addition to these four residues, A467 interacts with the 7-methoxy group of DIMBOA. All residues but W378 are variable among beta-glucosidases that differ in substrate specificity, supporting the conclusion that these sites are the basis of aglycone recognition and binding (i.e., substrate specificity) in beta-glucosidases. The data also provide a plausible explanation for the competitive binding of dhurrin to maize beta-glucosidases with high affinity without being hydrolyzed.

The mechanism of substrate (aglycone) specificity in beta -glucosidases is revealed by crystal structures of mutant maize beta -glucosidase-DIMBOA, -DIMBOAGlc, and -dhurrin complexes.,Czjzek M, Cicek M, Zamboni V, Bevan DR, Henrissat B, Esen A Proc Natl Acad Sci U S A. 2000 Dec 5;97(25):13555-60. PMID:11106394^[4]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

References

↑ Esen A. Purification and Partial Characterization of Maize (Zea mays L.) beta-Glucosidase. Plant Physiol. 1992 Jan;98(1):174-82. PMID:16668611
↑ Czjzek M, Cicek M, Zamboni V, Bevan DR, Henrissat B, Esen A. The mechanism of substrate (aglycone) specificity in beta -glucosidases is revealed by crystal structures of mutant maize beta -glucosidase-DIMBOA, -DIMBOAGlc, and -dhurrin complexes. Proc Natl Acad Sci U S A. 2000 Dec 5;97(25):13555-60. PMID:11106394 doi:10.1073/pnas.97.25.13555
↑ Cicek M, Esen A. Expression of soluble and catalytically active plant (monocot) beta-glucosidases in E. coli. Biotechnol Bioeng. 1999 May 20;63(4):392-400. PMID:10099619
↑ Czjzek M, Cicek M, Zamboni V, Bevan DR, Henrissat B, Esen A. The mechanism of substrate (aglycone) specificity in beta -glucosidases is revealed by crystal structures of mutant maize beta -glucosidase-DIMBOA, -DIMBOAGlc, and -dhurrin complexes. Proc Natl Acad Sci U S A. 2000 Dec 5;97(25):13555-60. PMID:11106394 doi:10.1073/pnas.97.25.13555

1 Structural highlights
2 Function
3 Evolutionary Conservation
4 Publication Abstract from PubMed
5 See Also
6 References

Proteopedia Page Contributors and Editors (what is this?)

OCA

Retrieved from "http://52.214.119.220/wiki/index.php/1e4n"

@@ Line 8: / Line 8: @@
 <tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1e4n FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1e4n OCA], [http://www.rcsb.org/pdb/explore.do?structureId=1e4n RCSB], [http://www.ebi.ac.uk/pdbsum/1e4n PDBsum]</span></td></tr>
 </table>
+== Function ==
+[[http://www.uniprot.org/uniprot/BGLC_MAIZE BGLC_MAIZE]] Is implicated in many functions such as ABA metabolism, hydrolysis of conjugated gibberellins, conversion of storage forms of cytokinins to active forms. Also acts in defense of young plant parts against pests via the production of hydroxamic acids from hydroxamic acid glucosides. Enzymatic activity is highly correlated with plant growth. The preferred substrate is DIMBOA-beta-D-glucoside. Hydrolyzes the chromogenic substrate 6-bromo-2-naphthyl-beta-D-glucoside (6BNGlc) and various artificial aryl beta-glucosides. No activity with cellobiose, arbutin, gentiobiose, linamarin or dhurrin as substrates.<ref>PMID:16668611</ref> <ref>PMID:11106394</ref> <ref>PMID:10099619</ref>
 == Evolutionary Conservation ==
 [[Image:Consurf_key_small.gif|200px|right]]

1e4n

From Proteopedia

Revision as of 18:30, 25 December 2014

CRYSTAL STRUCTURE OF THE INACTIVE MUTANT MONOCOT (MAIZE ZMGLU1) BETA-GLUCOSIDASE ZMGLU E191D IN COMPLEX WITH THE NATURAL AGLYCONE DIMBOA

Structural highlights

Function

Evolutionary Conservation

Publication Abstract from PubMed

See Also

References

Contents

Proteopedia Page Contributors and Editors (what is this?)

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