A 4-AMINO-2-HYDROXYBUTYRATE ACTIVATING ENZYME FROM BUTIROSIN-PRODUCING BACILLUS-CIRCULANS

An enzyme catalyzing a 4-amino-2-hydroxybutyrate dependent ATP-PP(i)- exchange reaction has been partially purified from butirosin-producing cells of B. circulans by ammonium sulfate fractionation, gel filtration or sucrose gradient centrifugation and ion exchange chromatography on QAE-sepharose. No reaction was found with 4-aminobutyrate and diaminobutyrate. The protein coeluted with GroEL, which has been identified by alignment of the internal sequence KDGVITVEESK. A molecular mass of about 1,5 MDa has been estimated for the complex by gradient centrifugation. In SDS-polyacrylamide gels a protein band with an estimated size of about 500 KDa correlated with the enzyme activity. The activity was not found in non-producing cells and a non- producing mutant of B. circulans with an insertional inactivation in the butB gene. © 1993 Academic Press, Inc.