| Autor: |
J P, Boissel, T J, Kasper, H F, Bunn |
| Rok vydání: |
1988 |
| Předmět: |
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| Zdroj: |
The Journal of biological chemistry. 263(17) |
| ISSN: |
0021-9258 |
| Popis: |
The diversity of protein structure is significantly enhanced by cotranslational and posttranslational modifications. Structural features at the amino terminus are especially important contributors to protein function and stability. Amino-terminal processing of cytosolic proteins includes the cleavage of the initiator methionine and N alpha-acetylation. To better understand the rules that govern these cotranslational events, site-directed mutants of the human beta-globin gene encoding for all 19 amino acid replacements of Val-beta 1 were expressed in a cell-free transcription and translation system. The initiator methionine was 100% cleaved when the side chain of the adjacent residue was relatively small (radius of gyration less than 1.29 A), whereas the initiator methionine was 100% retained when the side chain was relatively large. The extent of N alpha-acetylation ranged from 0 to 100% depending on the amino-terminal sequence. The experimental results in this cell-free system faithfully mimic what occurs in nature as judged by the structures of normal and variant human hemoglobins as well as a broad spectrum of other cytosolic proteins. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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