Application of gene-shuffling for the rapid generation of novel [FeFe]-hydrogenase libraries

A gene-shuffling technique was identified, optimized and used to generate diverse libraries of recombinant [FeFe]-hydrogenases. Six native [FeFe]-hydrogenase genes from species of Clostridia were first cloned and separately expressed in Escherichia coli concomitantly with the assembly proteins required for [FeFe]-hydrogenase maturation. All enzymes, with the exception of C. thermocellum HydA, exhibited significant activity when expressed. Single-stranded DNA fragments from genes encoding the two most active [FeFe]-hydrogenases were used to optimize a gene-shuffling protocol and generate recombinant enzyme libraries. Random sampling demonstrates that several shuffled products are active. This represents the first successful application of gene-shuffling using hydrogenases. Moreover, we demonstrate that a single set of [FeFe]-hydrogenase maturation proteins is sufficient for the heterologous assembly of the bioinorganic active site of several native and shuffled [FeFe]-hydrogenases.