What Is the Primary Structure of a Polypeptide or Protein

Draw a structural formula for Cys-Arg-Met-Asn. Label the A/-terminal amino acid and the C-terminal amino acid. What is the net charge on this tetrapeptide at pH 6.0  

The backbone of Cys-Arg-Met-Asn, a tetrapeptide, is a repeating sequence of nitrogen-a-carbon-carbonyl.The net charge on 

The primary (1°) structure of a polypeptide or protein is the sequence of amino acids in its polypeptide chain. In this sense, the primary structure is a complete description of all covalent bonding in a polypeptide or protein. 

In 1953, Frederick Sanger of Cambridge University, England, reported the primary structure of the two polypeptide chains of the hormone insulin. Not only was this a remarkable achievement in analytical chemistry, but also it clearly established that the molecules of a given protein all have the same amino acid composition and the same amino acid sequence. Today, the amino acid sequences of over 20,000 different proteins are known, and the number is growing rapidly. 

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