Sandbox Reserved 1102: Difference between revisions
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The helicase active site has a serine residue that serves as a nucleophilic amino acid. This residue is essential for the catalytic activity of the enzyme.The serine protases present a catalytic triad composed of 3 amino acids His57 Asp102 and Ser195.These 3 amino acids have a specific interaction which is due to the folding of the protein. The tridimentional conformation of the protein brings closer these 3 residues. Their side chains have a specific function : | The helicase active site has a serine residue that serves as a nucleophilic amino acid. This residue is essential for the catalytic activity of the enzyme.The serine protases present a catalytic triad composed of 3 amino acids His57 Asp102 and Ser195.These 3 amino acids have a specific interaction which is due to the folding of the protein. The tridimentional conformation of the protein brings closer these 3 residues. Their side chains have a specific function : | ||
[[Image:Serine protease catalysis.png | thumb | upright=3 | Serine protease catalysis]] | [[Image:Serine protease catalysis.png | thumb | upright=3 | Serine protease catalysis]] | ||
Ser195: the hydroxyl group plays the role of a nucleophile that attack the substrate. | '''Ser195''': the hydroxyl group plays the role of a nucleophile that attack the substrate. | ||
His57: the nitrogen receives an hydrogen from the hydroxyl group of Ser195. | '''His57''': the nitrogen receives an hydrogen from the hydroxyl group of Ser195. | ||
Asp102: this amino acid allows to increase the electronegativity of His157 nitrogen by making hydrogen bond with His157. | '''Asp102''': this amino acid allows to increase the electronegativity of His157 nitrogen by making hydrogen bond with His157. | ||
All these reactions allows to cleave the substrate by attacking its carbonyl group. | All these reactions allows to cleave the substrate by attacking its carbonyl group. | ||
