Active Inclusion Bodies in the Multienzymatic Synthesis of UDP-N-acetylglucosamine.

Bacterial inclusion bodies (IBs) are still generally considered to be waste products of recombinant protein production, despite various studies that have challenged this conventional view in the last two decades, and have been proposed for use as immobilized enzymes in vivo for biocatalysis. Current advances in genetic and molecular biology make it possible to perform multienzymatic reactions or enzymatic cascades to synthesize valuable products. When cascades need cofactor regener tion, it is difficult to use "cheap" whole cells or their lysates, and "expensive" enzyme purification is required. The capture of enzymatic activity into active IBs (aIBs), well-separable protein aggregates from cell lysate, could represent a usable compromise between purified enzymes and cell lysates. It is shown here that the combination of two polyphosphate kinases (PPKs) in the form of aIBs leads to almost 10-fold ATP regeneration and 100% UTP utilization without degradation into adenosine or uridine. PPKs have been combined with N-acetylhexosamine 1-kinase and N-acetylglucosamine-1-phosphate uridyltransferase to produce valuable UDP-N-acetylglucosamine, but the described approach could be used in various multienzymatic syntheses to avoid enzyme purification and ensure nucleotide triphosphate regeneration.