Identification of the gene involved in over-production of a novel lipopeptide in an over-expressed mutant of pseudomonas gingeri

Tayyebeh Pilehchi,1,* Mahya ghaffari,2 Hassan roknizadeh,3

1. zanjan university of medical sience
2. zanjan university of medical sience
3. zanjan university of medical sience



Lipopeptides as secondary metabolites, produced by pseudomonads, can be used as biosurfactants and antimicrobial drugs in industry. their structures are consisted of a peptide head and a lipid tail. wlip (white line inducing principle) is a lipopeptide that forms white line reaction (wlr) against tolaasin producers. likewise, wlr is seen between tolaasin and a new lipopeptide produced by pseudomonas gingeri. a mutant library had been made by random mutagenesis approach in order to identify the genetic system of this new lipopeptide. an over-expressed mutant was found in the library. in current study the disrupted gene in respective mutant was identified.


We identified plasposon insertion site by plasposon rescue technique in the mutant and analyzed the knockouted gene and its phylogenetic relationship with other species by in silico analysis.


The affected gene was algx which synthesizes alginate o-acetyl transferase. this protein has a domain belonging to sgnh hydrolase superfamily. although members of this superfamily are esterase and lipase, some of them are transferase or bifunctional. it seems that algx protein of this mutant is probably bifunctional.


It seems that lipase function of algx protein was lost in this mutant, therefore lipid tail of this lipopeptide is protected from this lipase-transferase enzyme.


Pseudomonas gingeri, lipopeptide, over-expressed mutant, algx