PROPERTIES OF C-TERMINAL TRUNCATED DERIVATIVES OF THE ACTIVATOR, STRR, OF THE STREPTOMYCIN BIOSYNTHESIS IN STREPTOMYCES-GRISEUS

The StrR protein is a DNA-binding protein activating the transcription of streptomycin biosynthesis of Streptomyces griseus N2-3-11 and Stre ptomyces glaucescens. A putative helix-turn-helix motif located betwee n amino acid positions 207 and 227 of the StrR protein was identified as a prerequisite for its DNA-binding properties. Although, C-terminal truncated StrR proteins were able to interact with StrR-binding sites , they failed to activate transcription from the StrR-dependent promot or strB1p. Therefore, the C-terminal domain of StrR seemed to be neces sary for its function as transcriptional activator.