[Bacillus cereus chitinases: isolation and characteristics]. / Khitinazy Bacillus cereus: vydelenie i kharakteristika.

Three chitinases (M(r) = 68, 52 and 38 kDa) have been isolated from the cultural filtrate of Bacillus cereus strain VKPM B-6838 by stepwise hydrophobic chromatography on butyl-Toyopearl and gel filtration on Superdex 75 (FPLC). The chitinases are stable in the pH range 4-10 and have the same pH optimum of activity. The 68 and 38 kDa enzymes display the highest activity at 60 degrees C. while the 52 kDa chitinase-at 50 degrees C. In contrast with the 68- and 52 kDa enzymes, the 38 kDa chitinase hydrolyzes not only colloidal but also "crystalline" chitin and chitosan. None of the chitinases hydrolyzes chitobiose. The N-terminal sequences (10 amino acids) of the 52 and 38 kDa chitinases do not reveal structural similarity between themselves or to other known bacterial chitinases. The 68 kDa chitinase is not immunologically related to the 52 and 38 kDa enzymes. The results obtained suggest that the 68, 52 and 38 kDa chitinase are the unique proteins.

[Cloning and expression in Bacillus subtilis of the gene for neutral protease of Bacillus brevis]. / Klonirovanie i ékspressiia v Bacillus subtilis gena neitral'noi proteazy Bacillus brevis.

Plasmids pCB20 and pCB22 were used for cloning and expression of the Bac brevis 7882 neutral protease gene in Bac. subtilis cells. The protease-containing fragments of 13 and 14 kb were cloned in pCB20 plasmid based on replication region of Streptococci plasmid pSM19035. Expression of the gene was shown to take place in Bac. subtilis. Application of vegetative promoters of the previously identified expression unit EU19035 greatly increases the expression of the protease in Bac. subtilis. Bac. subtilis cells, expressing the gene of Bac. brevis neutral protease, do not sporulate, are considerably larger than the cells which do not contain the gene and form multicellular structures.