A miniature cellulosome with novel interaction modes

Cellulosomes are efficient enzymatic nanomachines which have arisen for the degradation of cellulosic biomass. They are found abundantly in soil-dwelling microbes and bacteria which thrive in the stomachs of ruminant mammals. Two protein domains, cohesins and dockerins, characterise cellulosomes. These domains interact with each other to form enormous complexes with as many as 130 individual proteins. Annotation of the genome of Cellulosilyticum lenotcellum DSM 5427 revealed one single cohesin and one single dockerin domain. This pales in comparison to most cellulosomal organisms. We have recombinantly produced the proteins which bear these domains and demonstrated cellulase activity, which is enhanced by interaction between the two proteins. Moreover we have identified additional novel interacting partners for this unique cellulosome complex. This broadens the repertoire and definitions of cellulosomes overall.