Designed Heme-Cage β-Sheet Miniproteins

Angewandte Chemie - International Edition

5 years ago

Designed Heme-Cage β-Sheet Miniproteins

Xiangyang Wu, Surajit Bhattacharjya, Areetha D'Souza, Edwin Kok Lee Yeow

The structure and function of naturally occurring proteins are governed by a large number of amino acids (≥100). The design of miniature proteins with desired structures and functions not only substantiates our knowledge about proteins but can also contribute to the development of novel applications. Excellent progress has been made towards the design of helical proteins with diverse functions. However, the development of functional β-sheet proteins remains challenging. Herein, we describe the construction and characterization of four-stranded β-sheet miniproteins made up of about 19 amino acids that bind heme inside a hydrophobic binding pocket or “heme cage” by bis-histidine coordination in an aqueous environment. The designed miniproteins bound to heme with high affinity comparable to that of native heme proteins. Atomic-resolution structures confirmed the presence of a four-stranded β-sheet fold. The heme–protein complexes also exhibited high stability against thermal and chaotrope-induced unfolding. Stripped to the bone: A set of four-stranded β-sheet peptides designed to bind heme within an extended pocket or “heme cage” were found to show heme-binding affinity comparable to that of their native counterparts (see picture). The resulting peptide–heme complexes were highly resilient to thermal and chemical denaturation.

Publisher URL: http://onlinelibrary.wiley.com/resolve/doi

DOI: 10.1002/anie.201702472