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Characterization of a novel phenazine antibiotic gene cluster in Erwinia herbicola Eh1087
Author(s) -
Giddens Stephen R.,
Feng Yunjiang,
Mahanty H. Khris
Publication year - 2002
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1046/j.1365-2958.2002.03048.x
Subject(s) - biology , phenazine , gene cluster , complementation , gene , transposable element , mutant , plasmid , genetics , escherichia coli , erwinia , microbiology and biotechnology , biochemistry
Summary Erwinia herbicolastrain Eh1087 produces the broad‐spectrum phenazine antibioticD‐alanylgriseoluteic acid (AGA). In this report, a cluster of 16ehp(Erwiniaherbicolaphenazine) plasmid genes required for the production of AGA by Eh1087 is described. The extent of the gene cluster was revealed by the isolation of 82 different Eh1087 AGA−mutants, all found to possess single mini‐Tn5lacZ2insertions within a 14 kbp DNA region. Additional transposon insertions that did not affect antibiotic production by Eh1087 were created to define the boundaries of the gene cluster. The size and location of genes between these boundaries were derived from a combination of DNA sequence analyses, minicell protein analyses and the correlation between mutation position and the production of coloured AGA intermediates by manyehpmutants. Precursor‐feeding and complementation experiments resulted in 15ehpgenes being assigned to one of four functional groups according to their role in the synthesis of AGA. Group 1 is required for the synthesis of the phenazine nucleus in the form of antibiotic precursor one (AP1, phenazine‐1,6‐dicarboxylic acid). Group 2 is responsible for conversion of AP1 to AP2, which is subsequently modified to AP3 (griseoluteic acid) and exported by the group 3 gene products. Group 4 catalyses the addition ofD‐alanine to AP3 to create AGA, independently of groups 1, 2 and 3. A gene that is divergently transcribed from the 15 AGA synthesisehp genes confers resistance to AGA.