Genetic code deduced protein sequence

The primary goal of peptide mapping is the verification of the amino acid sequence deduced from the genetic code of the recombinant protein. The protein backbone gets cleaved by typically two or three different endoproteinases like Lys-C, trypsin, and Glu-C to achieve maps with sequence-overlapping peptide fragments. These peptide mixtures can then be separated by LC or CE and analyzed on-line by MS to obtain sequence information. Often simple mass analysis matches the predicted primary sequence of the protein. However, sometimes mutations can lead to isobaric masses of peptides that can be overseen, if no further sequence analysis like N-terminal Edman sequencing and MS/MS is carried out. 

The sequence of a protein can be determined using recombinant DNA technology to identify and sequence the piece of DNA encoding the protein. The amino acid sequence of the protein can then be deduced from its DNA sequence using the genetic code. 

In contemporary biochemistry the amino acid sequence of a protein is much more likely to be determined indirectly from the sequence of the DNA that encodes the protein or, in the case of eukaryotes, from the sequence of cDNA made from mRNA encoding it. This is because DNA sequences can be determined far more rapidly and accurately than protein sequences. Since the genetic code is known, it is a simple matter to deduce the... 

Isolation and Characterization of cDNA Clones Encoding the Poly-phenolic Protein. Characterization of the primary amino acid sequence of the mussel adhesive protein has been hindered by the large size of the protein and the repetitiveness of the amino acids. In such cases, the practical (and perhaps only) approach for determining the complete amino acid sequence is to clone DNA sequences encoding the protein and to deduce the amino acid sequence from the genetic code carried by that DNA. To accomplish this, we obtained mRNA from mussels and synthesized cDNA in vitro. 

Fig. S. Frameshift mutations the two partial amino-acid sequences have been determined by Streisinger et a/. they are part of a protein produced by the bacterial virus T4. The base sequence has been deduced theoretically from the genetic code, the pair of frameshift mutations has removed one adenine and inserted another guanine, fifteen bases further on.

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