PMID: 29634929

Authors:

Miyafusa T, Shibuya R, Honda S

Title:

Structural insights into the backbone-circularized granulocyte colony-stimulating factor containing a short connector.

Journal:

Biochem Biophys Res Commun. 2018 Apr 16. pii: S0006-291X(18)30808-8. doi:, 10.1016/j.bbrc.2018.04.045.

Abstract:

Backbone circularization is a powerful approach for enhancing the structural stability of polypeptides. Herein, we present the crystal structure of the circularized variant of the granulocyte colony-stimulating factor (G-CSF) in which the terminal helical region was circularized using a short, two-amino acid connector. The structure revealed that the N- and C-termini were indeed connected by a peptide bond. The local structure of the C-terminal region transited from an alpha helix to 310 helix with a bend close to the N-terminal region, indicating that the structural change offset the insufficient length of the connector. This is the first-ever report of a crystal structure of the backbone of a circularized protein. It will facilitate the development of backbone circularization methodology.