Distributions of amino acid residues in proteins show that proline is overrepresented in sequence positions following two basic residues (), i.e. at sites similar to those susceptible to proteolytic cleavages of hormonal pro-forms. Conformational correlations further show that -Pro sequences are often (8/11) not adiacent to elements of secondary structure, whereas the opposite applies to -nonPro sequences (82/103 adjacent to elements of secondary structure). These distribution patterns from proteins in general also seem applicable in individual protein groups as demonstrated for some dehydrogenases. It appears possible that -nonPro constitutes a restricted sequence, n proteins, and that proline, in addition to elements of secondary structure, contributes a means of avoiding unacceptable proteolytic processings of proteins in general.
- © 1983 The Biochemical Society