Hyperthermophilic asparaginase mutants with enhanced substrate affinity and antineoplastic activity: structural insights on their mechanism of action
| Autor: | Ramendra Pati Pandey, Goutam Dev Mukherjee, Bishwajit Kundu, Prashant Mishra, Anita Kamra Verma, Saurabh Bansal, Ankit Srivastava |
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| Rok vydání: | 2011 |
| Předmět: |
Models
Molecular Hot Temperature Cell Survival Archaeal Proteins Mutant Molecular Sequence Data Antineoplastic Agents HL-60 Cells Molecular Dynamics Simulation Biochemistry Glutaminase activity Substrate Specificity Catalytic Domain Cell Line Tumor Catalytic triad Enzyme Stability Genetics Asparaginase Humans Amino Acid Sequence Molecular Biology chemistry.chemical_classification biology Dose-Response Relationship Drug Sequence Homology Amino Acid Chemistry Circular Dichroism Proteolytic enzymes Wild type Active site biology.organism_classification Pyrococcus furiosus Kinetics Enzyme Spectrometry Fluorescence Mutation biology.protein Thermodynamics Tyrosine K562 Cells Biotechnology |
| Zdroj: | FASEB journal : official publication of the Federation of American Societies for Experimental Biology. 26(3) |
| ISSN: | 1530-6860 |
| Popis: | Thermophilic l-asparaginases display high stability and activity at elevated temperatures. However, they are of limited use in leukemia therapy because of their low substrate affinity and reduced activity under physiological conditions. In an attempt to combine stability with activity at physiological conditions, 3 active-site mutants of Pyrococcus furiosus l-asparaginase (PfA) were developed. The mutants, specifically K274E, showed improved enzymatic properties at physiological conditions as compared to the wild type. All variants were thermodynamically stable and resistant to proteolytic digestion. None of the enzymes displayed glutaminase activity, a highly desirable therapeutic property. All variants showed higher and significant killing of human cell lines HL60, MCF7, and K562 as compared to the Escherichia coli l-asparaginase. Our study revealed that increased substrate accessibility through the active site loop plays a major role in determining activity. A new mechanistic insight has been proposed based on molecular dynamics simulated structures, where dynamic flipping of a critical Tyr residue is responsible for the activity of thermophilic l-asparaginases. Our study not only resulted in development of PfA mutants with combination of desirable properties but also gave a mechanistic insight about their activity. |
| Databáze: | OpenAIRE |
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