Structural Requirements for the Specific Recognition of an m7G mRNA Cap
| Autor: | Jordan W. Thomas, Pi-Chen Hsu, Mary R. Hodel, Curt H. Hagedorn, Alec E. Hodel, Laura J. Taylor |
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| Rok vydání: | 2000 |
| Předmět: |
RNA Caps
Stereochemistry Phenylalanine Static Electricity Stacking Glutamic Acid Vaccinia virus Biochemistry Viral Proteins Peptide Initiation Factors Flavins Gene expression Moiety RNA Messenger chemistry.chemical_classification Messenger RNA Guanosine Chemistry Hydrogen bond Circular Dichroism EIF4E Tryptophan Hydrogen Bonding Affinities Amino acid Eukaryotic Initiation Factor-4E Spectrometry Fluorescence Amino Acid Substitution Mutagenesis Site-Directed Tyrosine |
| Zdroj: | Biochemistry. 39:13730-13736 |
| ISSN: | 1520-4995 0006-2960 |
| DOI: | 10.1021/bi000623p |
| Popis: | 7-Methylguanosine (m(7)G), also known as the mRNA "cap", is used as a molecular tag in eukaryotic cells to mark the 5' end of messenger RNAs. The mRNA cap is required for several key events in gene expression in which the m(7)G moiety is specifically recognized by cellular proteins. The configurations of the m(7)G-binding pockets of a cellular (eIF4E) and a viral (VP39) cap-binding protein have been determined by X-ray crystallography. The binding energy has been hypothesized to result from a pi-pi stacking interaction between aromatic residues sandwiching the m(7)G base in addition to hydrogen bonds between the base and acidic protein side chains. To further understand the structural requirements for the specific recognition of an m(7)G mRNA cap, we determined the effects of amino acid substitutions in eIF4E and VP39 cap-binding sites on their affinity for m(7)GDP. The requirements for residues suggested to pi-pi stack and hydrogen bond with the m(7)G base were examined in each protein by measuring their affinities for m(7)GDP by fluorimetry. The results suggest that both eIF4E and VP39 require a complicated pattern of both orientation and identity of the stacking aromatic residues to permit the selective binding of m(7)GDP. |
| Databáze: | OpenAIRE |
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