Specificity studies on retroviral proteinase from myeloblastosis-associated virus
| Autor: | Jiri Velek, Ivo Bláha, Miloslav Trávníček, L. Pavlíčková, Juraj Sedlacek, Petr Štrop, Vladimír Kostka, Jan Konvalinka, Dalibor Stys |
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| Rok vydání: | 1991 |
| Předmět: |
Molecular Sequence Data
Retroviridae Proteins Sodium Chloride Cleavage (embryo) Biochemistry Avian sarcoma virus Substrate Specificity Endopeptidases Aspartic Acid Endopeptidases Amino Acid Sequence Enzyme kinetics Binding site Peptide sequence chemistry.chemical_classification Avian Myeloblastosis Virus Rous sarcoma virus Binding Sites Avian Leukosis Virus biology Hydrolysis Serum Albumin Bovine Hydrogen-Ion Concentration biology.organism_classification Genes gag Kinetics Enzyme Avian Sarcoma Viruses chemistry Ionic strength Peptide Hydrolases |
| Zdroj: | Biochemistry. 30:3437-3443 |
| ISSN: | 1520-4995 0006-2960 |
| Popis: | The specificity of the p15 proteinase of myeloblastosis-associated virus (MAV) was tested with nonviral high molecular weight substrates and with synthetic peptides. Peptides with sequences spanning known cleavage sites in viral polyproteins of Rous sarcoma virus (RSV) and avian leukemia viruses, as well as in BSA and HSA, were synthesized, and the rate of their cleavage by the MAV proteinase was compared. Synthetic peptides require for successful cleavage at least 4 residues at the N-terminal side and 3 residues at the C-terminal side. The proteinase shows a preference for hydrophobic residues with bulky side chains (Met, Tyr, Phe) in P3, although Arg and Gln can also be accepted. Small hydrophobic residues are required in P2 and P2', and large hydrophobic residues (Tyr, Met, Phe/p-nitro-Phe) are preferred in both P1 and P1'. The difference between the specificity of the p15 proteinase and that of the HIV-1 proteinase mostly pertains to position P2' of the substrate, where bulkier side chains are accepted by the HIV-1 proteinase (Richards et al., 1990). A good chromogenic substrate for the MAV and RSV proteinases was developed and used to further characterize the MAV proteinase activity with respect to ionic strength and pH. The activity of the proteinase is strongly dependent on ionic strength and pH. Both the kcat and Km values contribute to a higher cleavage efficiency at higher salt concentrations and show a bell-shaped pH dependence curve with a sharp maximum at pH 5.5 (kcat) and 6.5 (Km). |
| Databáze: | OpenAIRE |
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