The development of protein biochemistry (at the end of the 1950s) has led to
the purification of many proteins followed by the study – using crystallography –
of their three-dimensional structure and, in parallelwith this, their sequencing (identification
of the linking of amino acids).
The study of variants for a peptide chain then allowed – by identification of
amino acid substitutions, notably those caused by missensemutations in the coding
sequence of a gene – the exhaustive definition of the causal relationships between
each mutation, its molecular effect and its cellular, tissular and clinical effects in
many pathologies. Of these, the most intensely studied relationship has been for the
protein haemoglobin in the haemoglobinopathies.
Following this first revolution there were many medical applications, but these
were unfortunately limited by the fact that the study of proteins can only be the
study of gene products, which requires that these products are present and accessible
for analysis.