- Michael Smith Laboratories
- Department of Microbiology and Immunology
- Department of Chemical and Biological Engineering
- Ph.D. (1967) University College, London, U.K.
Technologies involved in the production, isolation and engineering of industrially important proteins. My laboratory is focussed on technologies involved in the production, isolation and engineering of industrially important proteins. The work ranges from fermentation and process engineering to basic biochemistry and genetic engineering. A major interest is the cellulase system of the bacterium Cellulomonas fimi. In a collaborative project with Drs. C.A. Haynes and R.A.J. Warren, seven genes coding for the major components of the cellulase system of Cellulomonas fimi have been cloned and expressed in a variety of different organisms. Current work involves modifying these enzymes to enhance their activity or alter their specificity. We have identified discrete domains in all the C. fimi endoglucanases and exoglucanases which mediate strong binding to cellulose and which are structurally distinct from the respective catalytic domains. Using recombinant DNA techniques we have been able to engineer fusion proteins incorporating the cellulose-binding domain as an affinity tag. In this way the cellulose-binding domains of cellulases can be used to confer adhesive properties to enzymes and other functional proteins. Work is underway to characterize these binding domains, to investigate ways of modifying their affinities by protein engineering, and to use these domains to develop methods for the purification of desired polypeptides and for enzyme and cell immobilization. Various technologies that allow spe-cific cleavage of designed polypeptides from the cellulose-binding domains are being investigated. In many cases, proteins of therapeutic value can only be produced in mammalian cell hosts. The large-scale culti-vation of these cells presents a number of challenges. Work is underway to find ways of attaining higher cell and product yields and to develop new methods for monitoring and controlling the biological activity of growing cells.