Sandbox Reserved 655: Difference between revisions

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== '''Structure''' ==

In the past 20 years, researchers have found that endoglucanases cannot break down polysaccharides efficiently without the help of non-catalytic carbohydrate-binding modules. Thus, endoglucanase is mostly found in the form of a complex that is made up of three separate domains. The main domain contains the large, globular catalytic domain which expresses the active site. A loop of the protein chain forms a tunnel that encloses the active site. This is attached at the O-glycosylated B block hinge region of the catalytic domain to the smaller, globular CBM at its C-terminal A block by a linker peptide made up of proline, serine, and threonine (Nimlos, et al., 2007).The overall shape of the complex looks like a tadpole, with the A and B blocks forming the extended tail and the catalytic domain forming the head (Pilz, et al., 1990). The CBM facilitates the enzyme by binding the complex to the cellulose, thus maintaining the proximity of the enzyme and the substrate. It can also target areas of the cellulose that are specific to the enzyme complex. In addition, the CBM itself can disrupt the structure of the cellulose and thus expose the substrate more to the enzyme. The aromatic amino acid residues and planar architecture of the CBM binding sites are complementary to the hydrophobic sites of cellulose chains (hydrophobic 110 face) (Figure 3). This exposes the beta-D-glucopyranose rings in the chair conformation, which have their alpha and beta faces having either two or three axial hydrogens exposed and ring hydroxyl groups in the equatorial position, allowing the CBMs to bind efficiently (Nimlos, et al., 2007). The thermodynamic forces that drive this interaction is controversial, but most researchers postulate that it comes from the positive entropy when the water molecules are released from the protein and ligand (Boraston, et al., 2004).

In the past 20 years, researchers have found that endoglucanases cannot break down polysaccharides efficiently without the help of non-catalytic carbohydrate-binding modules. Thus, endoglucanase is mostly found in the form of a complex that is made up of three separate domains. The main domain contains the large, globular catalytic domain which expresses the active site. A loop of the protein chain forms a tunnel that encloses the <scene name='Sandbox_Reserved_655/Active_site/1'>active site</scene>.

This is attached at the O-glycosylated B block hinge region of the catalytic domain to the smaller, globular CBM at its C-terminal A block by a linker peptide made up of proline, serine, and threonine (Nimlos, et al., 2007).The overall shape of the complex looks like a tadpole, with the A and B blocks forming the extended tail and the catalytic domain forming the head (Pilz, et al., 1990). The CBM facilitates the enzyme by binding the complex to the cellulose, thus maintaining the proximity of the enzyme and the substrate. It can also target areas of the cellulose that are specific to the enzyme complex. In addition, the CBM itself can disrupt the structure of the cellulose and thus expose the substrate more to the enzyme. The aromatic amino acid residues and planar architecture of the CBM binding sites are complementary to the hydrophobic sites of cellulose chains (hydrophobic 110 face) (Figure 3). This exposes the beta-D-glucopyranose rings in the chair conformation, which have their alpha and beta faces having either two or three axial hydrogens exposed and ring hydroxyl groups in the equatorial position, allowing the CBMs to bind efficiently (Nimlos, et al., 2007). The thermodynamic forces that drive this interaction is controversial, but most researchers postulate that it comes from the positive entropy when the water molecules are released from the protein and ligand (Boraston, et al., 2004).

Sandbox Reserved 655: Difference between revisions

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 == '''Structure''' ==
-In the past 20 years, researchers have found that endoglucanases cannot break down polysaccharides efficiently without the help of non-catalytic carbohydrate-binding modules. Thus, endoglucanase is mostly found in the form of a complex that is made up of three separate domains. The main domain contains the large, globular catalytic domain which expresses the active site. A loop of the protein chain forms a tunnel that encloses the active site. This is attached at the O-glycosylated B block hinge region of the catalytic domain to the smaller, globular CBM at its C-terminal A block by a linker peptide made up of proline, serine, and threonine (Nimlos, et al., 2007).The overall shape of the complex looks like a tadpole, with the A and B blocks forming the extended tail and the catalytic domain forming the head (Pilz, et al., 1990). The CBM facilitates the enzyme by binding the complex to the cellulose, thus maintaining the proximity of the enzyme and the substrate. It can also target areas of the cellulose that are specific to the enzyme complex. In addition, the CBM itself can disrupt the structure of the cellulose and thus expose the substrate more to the enzyme. The aromatic amino acid residues and planar architecture of the CBM binding sites are complementary to the hydrophobic sites of cellulose chains (hydrophobic 110 face) (Figure 3). This exposes the beta-D-glucopyranose rings in the chair conformation, which have their alpha and beta faces having either two or three axial hydrogens exposed and ring hydroxyl groups in the equatorial position, allowing the CBMs to bind efficiently (Nimlos, et al., 2007). The thermodynamic forces that drive this interaction is controversial, but most researchers postulate that it comes from the positive entropy when the water molecules are released from the protein and ligand (Boraston, et al., 2004).
+In the past 20 years, researchers have found that endoglucanases cannot break down polysaccharides efficiently without the help of non-catalytic carbohydrate-binding modules. Thus, endoglucanase is mostly found in the form of a complex that is made up of three separate domains. The main domain contains the large, globular catalytic domain which expresses the active site. A loop of the protein chain forms a tunnel that encloses the <scene name='Sandbox_Reserved_655/Active_site/1'>active site</scene>.
+ This is attached at the O-glycosylated B block hinge region of the catalytic domain to the smaller, globular CBM at its C-terminal A block by a linker peptide made up of proline, serine, and threonine (Nimlos, et al., 2007).The overall shape of the complex looks like a tadpole, with the A and B blocks forming the extended tail and the catalytic domain forming the head (Pilz, et al., 1990). The CBM facilitates the enzyme by binding the complex to the cellulose, thus maintaining the proximity of the enzyme and the substrate. It can also target areas of the cellulose that are specific to the enzyme complex. In addition, the CBM itself can disrupt the structure of the cellulose and thus expose the substrate more to the enzyme. The aromatic amino acid residues and planar architecture of the CBM binding sites are complementary to the hydrophobic sites of cellulose chains (hydrophobic 110 face) (Figure 3). This exposes the beta-D-glucopyranose rings in the chair conformation, which have their alpha and beta faces having either two or three axial hydrogens exposed and ring hydroxyl groups in the equatorial position, allowing the CBMs to bind efficiently (Nimlos, et al., 2007). The thermodynamic forces that drive this interaction is controversial, but most researchers postulate that it comes from the positive entropy when the water molecules are released from the protein and ligand (Boraston, et al., 2004).