Discovering Biomolecules with Huisgenase Activity: Designed Repeat Proteins as Biocatalysts for (3 + 2) Cycloadditions

March 24, 2020

Title

Discovering Biomolecules with Huisgenase Activity: Designed Repeat Proteins as Biocatalysts for (3 + 2) Cycloadditions

Author

Iván Rivilla, Mikel Odriozola-Gimeno, Antonio Aires, Ana Gimeno, Jesús Jiménez-Barbero, Miquel Torrent-Sucarrat, Aitziber L. Cortajarena, Fernando P. Cossíosío

Year

2020

Journal

JACS

Abstract

Designed repeat proteins catalyze the 1,3-dipolar reaction between an imine and a π-deficient dipolarophile in THF solution to form unnatural nitroproline esters, a reaction that no enzyme can catalyze. NMR studies and mutation experiments show that both acidic and basic residues can catalyze the reaction. The diastereocontrol of the reaction depends on the flexibility of the protein and on the number and location of the active lysine and glutamate residues, which can participate independently or forming dyads that promote the formation of unusual diastereomeric cycloadducts. QM/MM calculations permit one to rationalize the origins of this Huisgenase activity and of its diastereocontrol.

Instrument

J-815

Keywords

Circular dichroism, Chemical stability, Secondary structure, Kinetics, Biochemistry, Organic chemistry