title: Calmodulin-like activity in mycobacteria.
abstract: Calmodulin-like activity has been reported for the first time in mycobacterial species, namely Mycobacterium tuberculosis BCG and M. smegmatis ATCC 14468. The activity was mainly located in the soluble fraction of the mycobacterial cells, Radioimmunoassay revealed maximum levels of calmodulin in young growing cells (early logarithmic phase of growth). Calmodulin-dependent phosphodiesterase activation assay revealed low activity (22%) of partially purified calmodulin either due to insufficient amount of calmodulin to activate phosphodiesterase or due to the presence of some factors interfering with the assay. Calmodulin antagonists, viz. trifluoperazine and phenothiazine, significantly inhibited the 32Pi incorporation into mycobacterial phospholipids. Similar inhibition was observed when EGTA (which removes calcium) was added to the medium. Significant inhibition of 32Pi incorporation in the presence of calmodulin antagonists suggested the involvement of calmodulin in mycobacterial phospholipid metabolism.
authors.affiliation: CSIR, Centre for Biochemicals, Delhi.
authors.forename: F A
authors.initials: FA
authors.lastname: Salih
authors.forename: N K
authors.initials: NK
authors.lastname: Kaushik
authors.forename: P
authors.initials: P
authors.lastname: Sharma
authors.forename: G V
authors.initials: GV
authors.lastname: Choudary
authors.forename: P S
authors.initials: PS
authors.lastname: Murthy
authors.forename: T A
authors.initials: TA
authors.lastname: Venkitasubramanian
mesh_terms: D002147:Calmodulin / Q000037:antagonists & inhibitors / Q000378:metabolism*; D054677:Cyclic Nucleotide Phosphodiesterases, Type 1; D009161:Mycobacterium / Q000378:metabolism*; D009169:Mycobacterium tuberculosis / Q000378:metabolism; D010727:Phosphoric Diester Hydrolases / Q000378:metabolism; D014268:Trifluoperazine / Q000494:pharmacology
chemical_list: D002147:Calmodulin; D014268:Trifluoperazine; D010727:Phosphoric Diester Hydrolases; D054677:Cyclic Nucleotide Phosphodiesterases, Type 1