Selective Biocatalytic Defunctionalization of Raw Materials

Biobased raw materials, such as carbohydrates, amino acids, nucleotides, or lipids contain valuable functional groups with oxygen and nitrogen atoms. An abundance of many functional groups of the same type, such as primary or secondary hydroxy groups in carbohydrates, however, limits the synthetic usefulness if similar reactivities cannot be differentiated. Therefore, selective defunctionalization of highly functionalized biobased starting materials to differentially functionalized compounds can provide a sustainable access to chiral synthons, even in case of products with fewer functional groups. Selective defunctionalization reactions, without affecting other functional groups of the same type, are of fundamental interest for biocatalytic reactions. Controlled biocatalytic defunctionalizations of biobased raw materials are attractive for obtaining valuable platform chemicals and building blocks. The biocatalytic removal of functional groups, an important feature of natural metabolic pathways, can also be utilized in a systemic strategy for sustainable metabolite synthesis.

The Cupin Protein Pac13 is Suggested by the Data to Be a Homodimer

Cupin proteins share a double-stranded β-helix fold, form one of the largest protein superfamilies, and possess remarkable functional diversity. They usually exist in homooligomeric states. Goss and co-workers recently reported that the cupin protein Pac13, which is a dehydratase that mediates the formation of the 3'-deoxy nucleoside of pacidamycins, is an unusual small monomer. However, a careful analysis of the biophysical and structural data provided by the authors suggests that Pac13 is in fact a homodimer, similar to many other cupin proteins.