Regulation of β-Lactam Antibiotic Biosynthesis by Carbon Sources

ChemInform ◽  
2004 ◽  
Vol 35 (12) ◽  
Author(s):  
Arnold L. Demain ◽  
Preeti Vaishnav
Keyword(s):  
Carbon Sources ◽  
Antibiotic Biosynthesis ◽  
Lactam Antibiotic

scholarly journals Insertional Inactivation of Methylmalonyl Coenzyme A (CoA) Mutase and Isobutyryl-CoA Mutase Genes in Streptomyces cinnamonensis: Influence on Polyketide Antibiotic Biosynthesis

1999 ◽  
Vol 181 (18) ◽  
pp. 5600-5605 ◽  
Author(s):  
Jan W. Vrijbloed ◽  
Katja Zerbe-Burkhardt ◽  
Ananda Ratnatilleke ◽  
Andreas Grubelnik-Leiser ◽  
John A. Robinson
Keyword(s):  
Sole Carbon Source ◽  
Coenzyme A ◽  
Carbon Sources ◽  
Antibiotic Biosynthesis ◽  
Polyketide Biosynthesis ◽  
Streptomyces Cinnamonensis ◽  
Insertional Inactivation ◽  
Hygromycin Resistance Gene ◽  
Monensin A ◽  
Coenzyme B

ABSTRACT The coenzyme B12-dependent isobutyryl coenzyme A (CoA) mutase (ICM) and methylmalonyl-CoA mutase (MCM) catalyze the isomerization of n-butyryl-CoA to isobutyryl-CoA and of methylmalonyl-CoA to succinyl-CoA, respectively. The influence that both mutases have on the conversion of n- and isobutyryl-CoA to methylmalonyl-CoA and the use of the latter in polyketide biosynthesis have been investigated with the polyether antibiotic (monensin) producer Streptomyces cinnamonensis. Mutants prepared by inserting a hygromycin resistance gene (hygB) into either icmA or mutB, encoding the large subunits of ICM and MCM, respectively, have been characterized. The icmA::hygB mutant was unable to grow on valine or isobutyrate as the sole carbon source but grew normally on butyrate, indicating a key role for ICM in valine and isobutyrate metabolism in minimal medium. ThemutB::hygB mutant was unable to grow on propionate and grew only weakly on butyrate and isobutyrate as sole carbon sources. 13C-labeling experiments show that in both mutants butyrate and acetoacetate may be incorporated into the propionate units in monensin A without cleavage to acetate units. Hence, n-butyryl-CoA may be converted into methylmalonyl-CoA through a carbon skeleton rearrangement for which neither ICM nor MCM alone is essential.

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