Substrate Induced Movement of the Metal Cofactor between Active and Resting State

Regulation of enzyme activity is vital for living organisms. In metalloenzymes, far-reaching rearrangements of the protein scaffold are generally required to tune the metal cofactor's properties by allosteric regulation. Here structural analysis of hydroxyketoacid aldolase from Sphingomonas wittichii RW1 (SwHKA) revealed a dynamic movement of...

Thermodynamics Determine the Diastereochemical Outcome of Catalytic Reactions

Diastereomers are characterised by an intrinsic energy difference, and thermodynamics dictate their distribution within a dynamic equilibrium. The characteristic mechanistic reversibility and non-ideal stereoselectivity of catalysts therefore simultaneously promote both synthesis and epimerization of products during the formation of...

Assessing the thiamine diphosphate dependent pyruvate dehydrogenase E1 subunit for carboligation reactions with aliphatic ketoacids

The synthetic properties of the Thiamine diphosphate (ThDP)-dependent pyruvate dehydrogenase E1 subunit from Escherichia coli (EcPDH E1) was assessed for carboligation reactions with aliphatic ketoacids. Due to its role in metabolism, EcPDH E1 was previously characterised with respect to its biochemical properties, but it was never applied...

Characterization of Enzymatically Synthesized Titania Thin Films Using Positron Annihilation Spectroscopy Reveals Low-Cost Approach for Organic/Inorganic Photovoltaic Cells

A new method is developed to produce mesoporous titania thin films at room temperature using the enzyme papain in a dip-coating procedure, providing low-cost titania films in a sustainable manner. Quartz crystal microbalance, positron annihilation Doppler broadening and lifetime spectroscopy, scanning electron microscopy, and X-ray...

Comparison of Enzymes Immobilised on Immobeads and Inclusion Bodies: A Case Study of a Trehalose Transferase

In this case study, we compare the performance of an enzyme immobilised using two different methods: i) as carrier-free catalytically active inclusion bodies or ii) as carrier-attached immobilised enzyme. To make this comparison we used a trehalose transferase from Thermoproteus uzoniensis fused to the fluorescent thermostable protein mCherry...

CH-π Interactions Promote the Conversion of Hydroxypyruvate in a Class II Pyruvate Aldolase

The class II hydroxy ketoacid aldolase A5VH82 from Sphingomonas wittichii RW1 (SwHKA) accepts hydroxypyruvate as nucleophilic donor substrate, giving access to synthetically challenging 3,4-dihydroxy-α-ketoacids. The crystal structure of holo-SwHKA in complex with hydroxypyruvate revealed CH-π interactions between the C−H bonds at C3 of...

Thermodynamically and Kinetically Controlled Reactions in Biocatalysis – from Concepts to Perspectives

The enzymatic synthesis of esters and peptides is unfavoured in aqueous solvent systems due to competing hydrolysis. This can be overcome by using energy rich substrate analogues: elimination of a good leaving group temporarily establishes more favourable equilibrium conditions, allowing for (nearly) complete conversion. While kinetically...