Chymotrypsin: Difference between revisions
From Proteopedia
Jump to navigationJump to search
Alice Harmon (talk | contribs) No edit summary |
Alice Harmon (talk | contribs) |
||
| Line 15: | Line 15: | ||
The <scene name='38/387136/Bovine_chymotrypsin_active_sit/1'>substrate-binding site</scene>, can be seen in this view with the inhibitor in light gray ball & stick with its phenyl group in orchid. By moving the structure back and forth with your mouse, it is easy to see that the phenyl group is located in the hydrophobic binding pocket of the enzyme. This binding pocket determines the enzyme's preference for cleavage of peptides on the C-terminal side of aromatic residues. | The <scene name='38/387136/Bovine_chymotrypsin_active_sit/1'>substrate-binding site</scene>, can be seen in this view with the inhibitor in light gray ball & stick with its phenyl group in orchid. By moving the structure back and forth with your mouse, it is easy to see that the phenyl group is located in the hydrophobic binding pocket of the enzyme. This binding pocket determines the enzyme's preference for cleavage of peptides on the C-terminal side of aromatic residues. | ||
This view shows the <scene name='38/387136/Bovine_chymotrypsin_active_sit/3'>carbonyl group of the inhibitor</scene> in CPK colors. The triflouromethyl group is bound to the carbonyl carbon via the yellow bond. In a peptide substrate, the triflouromethyl group would be replaced by the first amino acid residue of the rest of the peptide chain, and the yellow bond would be the bond that is cleaved. The carbonyl carbon of the inhibitor is 1. | This view shows the <scene name='38/387136/Bovine_chymotrypsin_active_sit/3'>carbonyl group of the inhibitor</scene> in CPK colors. The triflouromethyl group is bound to the carbonyl carbon via the yellow bond. In a peptide substrate, the triflouromethyl group would be replaced by the first amino acid residue of the rest of the peptide chain, and the yellow bond would be the bond that is cleaved. The carbonyl carbon of the inhibitor is 1.52 Å away from the side chain oxygen of serine 195, and this indicates they are covalently bound (bond indicated by dotted line). Thus, this structure is similar to the '''tetrahedral intermediate''' that is formed during the cleavage reaction. The negative charge that develops on the carbonyl oxygen of the substrate is stabilized by hydrogen bonds to the backbone nitrogens of Ser 195 and Gly 193, shown in blue spacefill. The hydrogen atoms involved in these hydrogen bonds are not shown. | ||
== 3D Structures of Chymotrypsin == | == 3D Structures of Chymotrypsin == | ||
