Single amino acid changes outside the active site significantly affect activity of glutathione S-transferases
| Autor: | Somphop Leetachewa, Chanikarn Boonchauy, Albert J. Ketterman, Umnaj Chanama, La-aied Prapanthadara, Nongkran Promtet, Peerada Prommeenate |
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| Rok vydání: | 2000 |
| Předmět: |
Models
Molecular DNA Complementary Molecular model Stereochemistry Molecular Sequence Data Biochemistry Residue (chemistry) Protein structure Anopheles Animals Amino Acid Sequence Binding site Molecular Biology Peptide sequence Glutathione Transferase chemistry.chemical_classification Binding Sites biology Base Sequence Active site Protein tertiary structure Amino acid Protein Structure Tertiary chemistry Amino Acid Substitution Insect Science biology.protein |
| Zdroj: | Insect biochemistry and molecular biology. 31(1) |
| ISSN: | 0965-1748 |
| Popis: | Glutathione S-transferases (GSTs: E.C. 2.5.1.18) are a multigene family of multifunctional dimeric proteins that play a central role in detoxication. Four allelic forms of the mosquito Anopheles dirus GST, adGST1-1, were cloned, expressed and characterized. The one or two amino acid changes in each allelic form was shown to confer different kinetic properties. Based on an available crystal structure, several of the residue changes were not in the putative substrate-binding pocket. Modeling showed that these insect Delta class GSTs also possess a hydrophobic surface pocket reported for Alpha, Mu and Pi class GSTs. The atom movement after replacement and minimization showed an average atom movement of about 0.1 A for the 0 to 25 A distance from the alpha carbon of the single replaced residue. This does not appear to be a significant movement in a static modeled protein structure. However, 200-500 atoms were involved with movements greater than 0.2 A. Dynamics simulations were performed to study the effects this phenomenon would exert on the accessible conformations. The data show that residues affecting nearby responsive regions of tertiary structure can modulate enzyme specificities, possibly through regulating attainable configurations of the protein. |
| Databáze: | OpenAIRE |
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