The alpha helix (α-helix) is a common motif in the secondary structure of proteins and is a righthand-spiral conformation (i.e. helix) in which every backbone N−H group donates a hydrogen bond to the backbone C.
Amino acids are organic compounds containing amine (-NH2) and carboxyl (-COOH) functional groups, along with a side chain (R group) specific to each amino acid.
The Asx motif is a commonly occurring feature in proteins and polypeptides.
The Asx turn is a structural feature in proteins and polypeptides.
The term C cap (C-cap, Ccap) describes an amino acid in a particular position within a protein or polypeptide.
A hydrogen bond is a partially electrostatic attraction between a hydrogen (H) which is bound to a more electronegative atom such as nitrogen (N), oxygen (O), or fluorine (F), and another adjacent atom bearing a lone pair of electrons.
The N-terminus (also known as the amino-terminus, NH2-terminus, N-terminal end or amine-terminus) is the start of a protein or polypeptide referring to the free amine group (-NH2) located at the end of a polypeptide.
Peptides (from Gr.: πεπτός, peptós "digested"; derived from πέσσειν, péssein "to digest") are short chains of amino acid monomers linked by peptide (amide) bonds.
Proteins are large biomolecules, or macromolecules, consisting of one or more long chains of amino acid residues.
Serine (symbol Ser or S) is an ɑ-amino acid that is used in the biosynthesis of proteins.
The ST turn is a structural feature in proteins and polypeptides.
Threonine (symbol Thr or T) is an amino acid that is used in the biosynthesis of proteins.