AN ENDO-N-ACETYL-BETA-D-GLUCOSAMINIDASE, ACTING ON THE DI-N-ACETYLCHITOBIOSYL PART OF N-LINKED GLYCANS, IS SECRETED DURING SPORULATION OF MYXOCOCCUS-XANTHUS

After the demonstration that Stigmatella aurantiaca DW4 secretes an en do N-acetyl-beta-D-glucosaminidase (ENGase), acting on the di-N-acetyl chitobiosyl part of N-linked glycans (S. Bourgerie, Y. Karamanos, T. G rard, and R. Julien, J, Bacteriol, 176:6170-6174, 1994), an ENGase act ivity having the same substrate specificity was also found to be secre ted during vegetative growth of Myxococcus xanthus DK1622. The activit y decreased in mutants known to secrete less protein than the wild typ e (Exc(+/-)), During submerged development, the activity was produced in two steps: the first increase occurred during the aggregation phase , and the second one occurred much later, during spore formation, This production was lower in developmental mutants impairing cell-cell sig naling, the late mutants (csg and dsg) being the most deficient, Final ly, when sporulation was obtained either by starvation in liquid shake flask culture or by glycerol induction, the activity was produced exc lusively by the wild-type cells during the maturation of the coat.