2.7.8.23 cloned and expressd at high levels in Escherichia coli 643771 2.7.8.23 gene cloned from a subgenomic library cloned by colony hybridisation in Escherichia coli AG1, subcloned into vector pET11a and overexpressed in Escherichia coli BL21(DE3) 643773 2.7.8.23 mutant NP71 constructed by gene replacement technique 643768, 643769 2.7.8.23 nucleotide sequence of gene isolated and cloned and expressed in Streptomyces lividans 66 using expression vector pIJ680 643772