Learning from Protein Engineering by Deconvolution of Multi‐Mutational Variants

Abstract

This review analyzes a development in biochemistry, enzymology and biotechnology that originally came as a surprise. As part of directed evolution of stereoselective enzymes in organic chemistry, the concept of partial or complete deconvolution of selective multi‐mutational variants was established and refined during the past 15 years. Early deconvolution experiments of stereoselective variants led to the finding that mutations can interact cooperatively or antagonistically with one another, not just additively. Later, this phenomenon was shown to be general. Molecular dynamics (MD) and quantum mechanics/molecular mechanics (QM/MM) computations were performed in order to shed light on the origin of non‐additivity at all stages of an evolutionary upward climb. Data of complete deconvolution can be used to construct unique multi‐dimensional rugged fitness pathway landscapes, which provide more mechanistic insight than traditional fitness landscapes. Along a related line, biochemists have long tested the result of introducing two point mutations in an enzyme for mechanistic reasons, followed by a comparison of the respective double mutant in so‐called double mutant cycles, which originally showed only additive effects, but more recently also uncovered cooperative and antagonistic non‐additive effects.