Protein sequencing amino acid function analysis

The protein of interest having been purified and its mass determined, the next analysis usually performed is to determine the protein s amino acid sequence, or primary structure. As stated previously (Section 3.2.1), a wealth of information about a protein s function and evolutionary history can often be obtained from the primary structure. Let us examine first how we can sequence a simple peptide, such as... 

Later we return to an analysis of the 1° structure of proteins and the methodology used in determining the amino acid sequence of polypeptide chains, but let s first consider the extraordinary variety and functional diversity of these most interesting macromolecules. 

Amino acid sequence analysis reveals that proteins with related functions often show a high degree of sequence similarity. Such findings suggest a common ancestry for these proteins. 

Moreover, molecular modeling is one key method of a wide range of computer-assisted methods to analyze and predict relationships between protein sequence, 3D-molecular structure, and biological function (sequence-structure-function relationships). In molecular pharmacology these methods focus predominantly on analysis of interactions between different proteins, and between ligands (hormones, drugs) and proteins as well gaining information at the amino acid and even to atomic level. 

The history of molecular biology has been a history of technological developments for determining the primary and tertiary structures of protein and nucleic acid molecules. Once the molecular structure is known, it provides clues to molecular functions. This is the principle of the structure-function relationship. Based on this principle the analysis of the amino acid sequence is performed to decipher the functional information from the sequence information. The analysis usually involves detection and prediction of empirical sequence—function relationships with additional consideration of known or predicted three-dimensional (3D) structures. Thus, the process can be represented schematically as ... 

A critical input in unraveling the catalytic mechanism of epoxide hydrolases has come from the identification of essential residues by a variety of techniques such as analysis of amino acid sequence relationships with other hydrolases, functional studies of site-directed mutated enzymes, and X-ray protein crystallography (e.g., [48][53][68 - 74]). As schematized in Fig. 10.6, the reaction mechanism of microsomal EH and cytosolic EH involves a catalytic triad consisting of a nucleophile, a general base, and a charge relay acid, in close analogy to many other hydrolases (see Chapt. 3). 

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