Cellulase and hemicellulase genes of Clostridium thermocellum from five independent collections contain few overlaps and are widely scattered across the chromosome.

Abstract

Five independent collections, comprising a total of 34 clones encoding cellulases, hemicellulases and cell surface proteins of Clostridium thermocellum, were searched for overlapping or contiguous DNA fragments. The clones were hybridized to large genomic restriction fragments separated by pulse-field electrophoresis. Clones hybridizing to the same fragment were further compared by hybridization to smaller fragments, by cross-hybridization and by restriction mapping. The probes hybridized to loci which were usually not clustered and were scattered over at least one third of the chromosome. Besides previously identified clusters, only two clones were found to be adjacent. Two pairs of clones appeared to contain the same genes cloned in duplicate, and one of the genes was shown to be cloned in triplicate.