1. Volume 9, Issue 11, Pages 1005-1016 (November 2001)
Catalytic Mechanisms and Reaction Intermediates along the Hydrolytic Pathway of a Plant β-D-glucan Glucohydrolase 
Maria Hrmova, Joseph N Varghese, Ross De Gori, Brian J Smith, Hugues Driguez, Geoffrey B Fincher 
Structure 
Volume 9, Issue 11, Pages (November 2001)
DOI: /S (01)

2. Figure 1
Inactivation of β-D-glucan Glucohydrolase by Conduritol B Epoxide
(a) Semilogarithmic plot of residual activity versus time at the indicated concentrations.
(b) Dependence of 1/kapp on the reciprocal of concentration
Structure 2001 9, DOI: ( /S (01) )

3. Figure 2
Comparative Peptide Mapping of Tryptic Fragments of Native and Conduritol B Epoxide-Inactivated β-D-glucan Glucohydrolase
(a) Tryptic digests of native (continuous line) and inactivated (dashed line) enzymes were separated, and the fractions, indicated by full and dashed arrows of the native and inactivated enzymes, respectively, were subjected to amino acid sequence analysis.
(b) The fraction indicated in bold is unique to the digest of the inactivated enzyme. The small peak at 47.2 min (asterisk) is an autolytic fragment of trypsin
Structure 2001 9, DOI: ( /S (01) )

4. Figure 3
Electron Density Map of the Cyclohexitol Ring and the D285 Residue in the Active Site of β-D-glucan Glucohydrolase
The C1 of the cyclohexitol ring and Oδ1285 are separated by 1.33 Å. The diaxial positions of the ester linkage through D285 at the C1 and the hydroxyl group at the C2 of the cyclohexitol ring are clearly visible. The electron density map was calculated from the observed structure factors and phases using the β-D-glucan glucohydrolase structure and excluding the bound glucose in the active site. The derived 2|Fo|-|Fc| and |Fo|-|Fc| Fourier syntheses are contoured at 1.2σ (magenta) and 3σ (green), respectively; Fo and Fc are the observed and calculated structure factors, respectively. The figure was prepared using O [44]
Structure 2001 9, DOI: ( /S (01) )

5. Figure 4
Stereo Representation of Ligands Bound in the Active Site of β-D-glucan Glucohydrolase
MOLSCRIPT [47] diagrams of the nearest hydrogen bonding interactions (dashed lines) between:
(a) Glucose.
(b) Cyclohexitol ring.
(c) 2-deoxy-2-fluoro-α-D-glucosyl moiety.
(d) S-cellobioside moiety.
and the contact amino acid residues.
Ligands are colored in cyan. The molecular surfaces of domains 1 and 2 are represented by transparent cyan and magenta surfaces, respectively, and are generated using GRASP [48]. Black, red, blue, yellow, and gray spheres represent carbon, oxygen, nitrogen, sulfur, and fluorine atoms, respectively. Water molecules are represented as red spheres. In (c), residues E220, E287, R291, and E491, along with Wat2 and Wat3, are not included, to improve the clarity of the data. The entrance to the active site in (b) and (c) is located perpendicularly to the page and is located toward the lower left hand corner in (a) and (d)
Structure 2001 9, DOI: ( /S (01) )

6. Figure 5
Bonding Interactions of Ligands in the Active Site of β-D-glucan Glucohydrolase
The following are shown in 4C1 conformation with atomic numbering of the C atoms:
(a) Glucose.
(b) Cyclohexitol ring.
(c) 2-deoxy-2-fluoro-α-D-glucosyl moiety.
(d) S-cellobioside moiety.
The dashed lines indicate hydrogen bonding, hydrophobic and ionic interactions between inhibitors, amino acid residues, and water molecules. Catalytic amino acid residues are shown. In contrast to Figure 4c, residues E220, E287, R291, and E491, along with Wat2 and Wat3, are included. All distances are expressed in Å and are drawn to scale where possible
Structure 2001 9, DOI: ( /S (01) )

7. Figure 6
Variation in COC Bond Angles and Relative Energies with CCOC Dihedral Angles for Covalent Complexes of an Acetate Anion with the 2H, 3H, 4H, 5H-oxonium Ion and with the 2-fluro Derivative of an Oxonium Ion
Solid and dashed lines indicate COC bond angles and relative energies, respectively. Geometries and energies were calculated at the HF/6-31G(d) level. Open circles indicate geometries of the Protein Data Bank inhibitor-protein complexes. We acknowledge that the correct chemical description in accordance with IUPAC nomenclature is 5-fluoro, but here we use the 2-fluoro annotations
Structure 2001 9, DOI: ( /S (01) )

8. Figure 7
Electron Density Map of the S-cellobioside Moiety in the Active Site of β-D-glucan Glucohydrolase
The derived 2|Fo|-|Fc| and |Fo|-|Fc| Fourier syntheses are contoured at 1.3σ. The figure was prepared using O
Structure 2001 9, DOI: ( /S (01) )

9. Figure 8
Kinetics and Hydrolytic Mechanism of a Family 3, Retaining Plant β-D-glucan Glucohydrolase
(a) Kinetics. The initial formation (k1) of the Michaelis complex (E-S) is preceded by the release of a noncovalently bound glucose molecule (Glc) from an enzyme-product complex (E∼Glc) in which the glucose product remains bound in the active site after a previous catalytic cycle. In the second step, the glycosidic linkage is cleaved (k2), and the glycone portion of the substrate becomes covalently attached to the enzyme to produce a metastable covalent glucosyl-enzyme intermediate (E.Glc). The aglycone part of the substrate (H-OR) is released. In the third step, the covalent glucosyl-enzyme intermediate is hydrolyzed (k3) by a water molecule, and the noncovalent enzyme-product complex (E∼Glc) is reformed. Product (Glc) is released when another substrate molecule (S) approaches the active site and forms the next Michaelis complex (E-S). First-order rate constants are shown (k1–k3).
(b) Hydrolytic mechanism. The double-displacement reaction mechanism at the anomeric chiral center proceeds through the protonation of the glucosidic oxygen via the acid/base E491. A covalent α-glucosyl-enzyme intermediate (E.Glc) is formed with D285, probably via oxonium and oxocarbenium intermediates. The final hydrolysis product, glucose, in which anomeric configuration is retained, remains bound in the active site and represents the enzyme-product complex (E∼Glc). The two catalytic amino acid residues D285 and E491 are eventually returned to their original protonation states. The involvement of an oxocarbenium-like transition state in place of the distinct oxonium and oxocarbenium intermediates is also shown. Substrate binding subsites −1 and +1 are marked
Structure 2001 9, DOI: ( /S (01) )