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Abstract:
Proteins are composed of linear chains of amino
acids. Upon synthesis in the cell, most proteins
must rapidly acquire a specific three-dimensional
structure, a process known as folding, before
they can perform their various biological func-
tions. Productive folding is often competed by
aggregation, owing to the high macromolecular
crowding of the cellular environment. Moreover,
the process of translation increases the danger of
misfolding, as incomplete nascent polypeptides
are not yet able to fold into stable structures in
many cases. To avoid these off-pathway reactions,
a class of proteins called molecular chaperones
has evolved in all organisms. They interact with
nascent or stress-denatured polypeptides, prevent
their aggregation and assist in folding and assem-
bly processes, often in an ATP-regulated manner.
These functions are especially important in condi-
tions of cell stress, and their failure is linked with
the manifestation of numerous age-dependent
degenerative diseases
