In the early 1980s, Raffi Lamed and I met at Tel Aviv University and commenced our work that led to the discovery of the cellulosome concept. Raffi had just completed postdoctoral tenures in the States and I was at the tail end of a postdoc at Tel Aviv University. Raffi approached me at the time with a description of how Clostridium thermocellum, an anaerobic thermophilic cellulolytic bacterium, bound very strongly to the cellulose substrate before it commences its degradation. We decided to study this phenomenon together.
The discovery of the cellulosome is a story of serendipity, a story of imagination, persistence, and a triumph over dogma. At the time, we weren’t looking for enzymes or cellulosomes at all. We simply sought a ‘cellulose-binding factor’ or ‘CBF’ on the cell surface of the anaerobic thermophilic bacterium, Clostridium thermocellum, which we inferred would account for the observation that the bacterium attaches strongly to the insoluble cellulose substrate prior to its degradation. We employed a then unconventional experimental approach, in which we isolated an adherence-defective mutant of the bacterium and prepared a specific polyclonal antibody for detection of the functional component. Surprisingly, we isolated a very large multi-subunit supramolecular complex, instead of a small protein. Rather than discarding the uninvited material, we were alert enough to follow up this intriguing finding experimentally. A combination of biochemical, biophysical, immunochemical and ultrastructural techniques, followed by molecular biological verification, led to the definition and proof of the cellulosome concept. The birth of the discrete, multi-enzyme cellulosome complex was thus documented. Today, cellulosomes have been confirmed in several but not all cellulolytic bacteria. The cellulosome-producing strains exhibit surprising diversity in the composition and architecture of the component parts.
You can read much more detailed accounts about the discovery and history of the cellulosome in the following reviews:
- Bayer, E. A., and Lamed, R. (2006) The cellulosome saga: Early history, p. 11-46. In Uversky, V. and Kataeva, I. A. (ed.), Cellulosome. Nova Science Publishers, Inc, New York.
- Bayer, E. A., Lamed, R., White, B. A., and Flint, H. J. (2008) From cellulosomes to cellulosomics. Chem. Rec. 8, 364-377.
In addition, you are invited to check out the three original articles:
- Bayer, E. A., Kenig, R., and Lamed, R. (1983) Adherence of Clostridium thermocellum to cellulose. J. Bacteriol. 156, 818-827.
- Lamed, R., Setter, E., and Bayer, E. A. (1983) Characterization of a cellulose-binding, cellulase-containing complex in Clostridium thermocellum. J. Bacteriol. 156, 828-836.
- Lamed, R., Setter, E., Kenig, R., and Bayer, E. A. (1983) The cellulosome — a discrete cell surface organelle of Clostridium thermocellum which exhibits separate antigenic, cellulose-binding and various cellulolytic activities. Biotechnol. Bioeng. Symp. 13, 163-181.