Combining chemistry and protein engineering for new-to-nature biocatalysis

Abstract

Biocatalysis, the application of enzymes to solve synthetic problems of human import, has blossomed into a powerful technology for chemical innovation. In the past decade, a threefold partnership, where nature provides blueprints for enzymatic catalysis, chemists introduce innovative activity modes with abiological substrates, and protein engineers develop new tools and algorithms to tune and improve enzymatic function, has unveiled the frontier of new-to-nature enzyme catalysis. In this perspective, we highlight examples of interdisciplinary studies which have helped to expand the scope of biocatalysis, including concepts of enzymatic versatility explored through the lens of biomimicry, to achieve both activities and selectivities that are not currently possible with chemocatalysis. We indicate how modern tools, such as directed evolution, computational protein design and machine learning-based protein engineering methods, have already impacted and will continue to influence enzyme engineering for new abiological transformations. A sustained collaborative effort across disciplines is anticipated to spur further advances in biocatalysis in the coming years.

Figure 1.. Biomimetic and enzymatic nitrene transfer for C-H insertion reactions.

(a) Biomimetic intramolecular tosylamidation using Fe(TPP)Cl as a catalyst.^, (b) Enzyme-catalyzed intramolecular tosylamidation using rabbit liver P450 LM3,4 as a biocatalyst. (c) Engineered P411_CIS-catalyzed asymmetric intramolecular tosylamidation. Bonds formed via nitrene C-H insertion are shown in red. e.e., enantiomeric excess; TPP, tetraphenylporphyrin; TTN, total turnover number.

Figure 2:. Representative examples of cofactor adaptation for abiological reactions with new-to-nature reactivity modes.

(a) The chemistry of metal porphyrins has been extended to hemoproteins for both carbene and nitrene transfer when presented with carbene and nitrene precursors.^– (b) Visible-light stimuli allows for flavoproteins to engage in biocatalytic photoredox transformations of alkyl halides.^– (c) Carbonic anhydrase uses silanes to generate an active zinc hydride intermediate for new reactions. His, histidine.

Figure 3:. Select examples of new-to-nature enzyme catalysis.

(a) Hemoprotein-catalyzed, stereodivergent cyclopropanation of unactivated olefin substrates. (b) P411-catalyzed bicyclobutane formation through sequential carbene additions across alkynes. (c) Asymmetric primary animation of benzylic C–H bonds catalyzed by P411s. (d) Biocatalytic, asymmetric hydroalkylation of styrenes via photochemical activation of flavins. (e) Asymmetric halolactonization catalyzed by halogenase enzymes. GDH, glucose dehydrogenase; d.r., diastereomeric ratio; e.e., enantiomeric excess; LEDs, light-emitting diodes; OD, optical density; Piv, pivaloyl; RT, room temperature; Tf, trifluoromethanesulfonyl; TTN, total turnover number; WCS, whole cell suspension.