Peptides and proteins find an ever-increasing number of applications in the biomedical and materials engineering
fields. The use of non-proteinogenic amino acids endowed with diverse physicochemical and structural features
opens the possibility to design proteins and peptides with novel properties and functions. Moreover, nonproteinogenic
residues are particularly useful to control the three-dimensional arrangement of peptidic chains,
which is a crucial issue for most applications. However, information regarding such amino acidssalso called
non-coded, non-canonical, or non-standardsis usually scattered among publications specialized in quite diverse
fields as well as in patents. Making all these data useful to the scientific community requires new tools and
a framework for their assembly and coherent organization. We have successfully compiled, organized, and
built a database (NCAD, Non-Coded Amino acids Database) containing information about the intrinsic
conformational preferences of non-proteinogenic residues determined by quantum mechanical calculations,
as well as bibliographic information about their synthesis, physical and spectroscopic characterization,
conformational propensities established experimentally, and applications. The architecture of the database is
presented in this work together with the first family of non-coded residues included, namely, R-tetrasubstituted
R-amino acids. Furthermore, the NCAD usefulness is demonstrated through a test-case application example.
