The chitinolytic system of Streptomyces olivaceoviridis

Abstract

Streptomyces olivaceoviridis secretes several chitinases. The characterized 59 kDa exochitinase consists of a C-terminal catalytic domain, one central region, and one N-terminal chitin-binding part (12 kDa). The presence of the binding domain was shown to be a prerequisite for an efficient degradation of crystalline α- and β-chitins. In addition to the chitinolytic enzymes, S. olivaceoviridis produces a so far unique chitin-binding protein (CHB1). Biochemical studies and immunofluorescence microscopy revealed, that the CHB1 protein binds specifically only to α-chitin from crab shell or fungi. The role of the novel lectinlike protein is at present being investigated. © 1995 Elsevier B.V.