Open AccessCloning and characterization of short‐chain N ‐acyl homoserine lactone‐producing Enterobacter asburiae strain L1 from lettuce leaves
Author(s) -
Lau Yin Yin,
How Kah Yan,
Yin WaiFong,
Chan KokGan
Publication year - 2018
Publication title -
microbiologyopen
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.881
H-Index - 36
ISSN - 2045-8827
DOI - 10.1002/mbo3.610
Subject(s) - chromobacterium violaceum , quorum sensing , homoserine , escherichia coli , bacteria , biology , strain (injury) , biofilm , biochemistry , microbiology and biotechnology , gene , chemistry , genetics , anatomy
In gram‐negative bacteria, bacterial communication or quorum sensing ( QS ) is achieved using common signaling molecules known as N ‐acyl homoserine lactones ( AHL ). We have previously reported the genome of AHL ‐producing bacterium, Enterobacter asburiae strain L1. In silico analysis of the strain L1 genome revealed the presence of a pair of luxI/R genes responsible for AHL ‐type QS , designated as eas IR . In this work, the 639 bp luxI homolog, encoding 212 amino acids, have been cloned and overexpressed in Escherichia coli BL 21 ( DE 3) pL ysS. The purified protein (~25 kD a) shares high similarity to several members of the LuxI family among different E asburiae strains. Our findings showed that the heterologously expressed EasI protein has activated violacein production by AHL biosensor Chromobacterium violaceum CV 026 as the wild‐type E . asburiae . The mass spectrometry analysis showed the production of N ‐butanoyl homoserine lactone and N –hexanoyl homoserine lactone from induced E . coli harboring the recombinant EasI, suggesting that EasI is a functional AHL synthase. E . asburiae strain L1 was also shown to possess biofilm‐forming characteristic activity using crystal violet binding assay. This is the first report on cloning and characterization of the luxI homolog from E . asburiae .