| 摘要 |
PROBLEM TO BE SOLVED: To provide a simple method for quickly synthesizing a heavy atom-substituted protein suitable for the X-ray crystal structural analysis for protein, particularly phase determination by MAD(multiwavelength anomalous diffraction) method. SOLUTION: This method for producing a protein suitable for its X-ray crystal structural analysis by the use of a cell-free protein synthetic system comprising a cell extract liquid, a nucleic acid encoding the protein and amino acids as the substrate for the protein synthesis, comprises synthesizing the protein using the above system characteristic in that at least one amino acid among the above-mentioned ones is a heavy atom-containing amino acid. In a preferred embodiment, the above system comprises a dialysis inner liquid and a dialysis outer liquid via a dialysis membrane, wherein the dialysis inner liquid includes the above- mentioned cell extract liquid and the above-mentioned nucleic acid encoding the protein, and the amino acids as the substrate for the protein synthesis is included in the dialysis inner liquid and/or the dialysis outer liquid. By the use of this method, the rate of introduction of the heavy atom-containing amino acid into the protein formed is extremely high, and compared to a method for protein synthesis using living cells, the objective heavy atom- containing protein can be produced very easily and in large quantities.
|
