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The ability to create efficient artificial enzymes for any chemical reaction is of great interest. Here, we describe a computational design method for increasing the catalytic efficiency of de novo enzymes by several orders of magnitude without relying on directed evolution and high-throughput screening. Using structural ensembles generated from dynamics-based refinement against X-ray diffraction data collected from crystals of Kemp eliminases HG3 ( k cat / K M 125 M -1 s -1 ) and KE70 ( k cat / K M 57 M -1 s -1 ), we design from each enzyme ≤10 sequences predicted to catalyze this reaction more efficiently. The most active designs display k cat / K M values improved by 100-250-fold, comparable to mutants obtained after screening thousands of variants in multiple rounds of directed evolution. Crystal structures show excellent agreement with computational models, with catalytic contacts present as designed and transition-state root-mean-square deviations of ≤0.65 Å. Our work shows how ensemble-based design can generate efficient artificial enzymes by exploiting the true conformational ensemble to design improved active sites.

We report synchrotron X-ray diffraction, photoconductivity, and photoluminescence investigations of methylammonium-lead-bromide (MAPbBr 3 ) under various stress conditions, supported by density-functional-theory (DFT) calculations. The properties of MAPbBr 3 show substantial dependence on the hydrostatic conditions. While nonhydrostatic compression of MAPbBr 3 leads to amorphization above 2.4 GPa, under quasi-hydrostatic (Ar) and hydrostatic (He) pressure, the sample remains in crystalline phases. A sequence of phase transitions between two cubic phases and orthorhombic Pnma phase is observed when using Ar, or no pressure-transmitting-medium (PTM). In helium-PTM only transitions between the two cubic structures and a new isostructural phase transition with a large volume collapse to a third cubic-phase at 2.7 GPa was observed. The photoluminescence measurements indicate a pressure-induced band gap-narrowing in the cubic phase I, and a blue-shift in the orthorhombic structure. DFT calculations illustrate that the dynamics of the organic molecules and the inorganic lattice, coupled via the N-H···Br hydrogen-bonding interactions, affect the Pb-Br distance and the bandgap evolution under pressure.