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Proteomic characterization of a pilR regulatory mutant of Azoarcus sp. strain BH72 with the aid of gel‐based and gel‐free approaches
Author(s) -
Hauberg Lena,
Schmidt Frank,
Scharf Christian,
Dörr Juliane,
Völker Uwe,
ReinholdHurek Barbara
Publication year - 2010
Publication title -
proteomics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.26
H-Index - 167
eISSN - 1615-9861
pISSN - 1615-9853
DOI - 10.1002/pmic.200900307
Subject(s) - regulon , mutant , proteome , biology , biochemistry , response regulator , regulator , two component regulatory system , gene
The proteome of the grass endophyte Azoarcus sp. strain BH72 was analyzed by a combination of gel‐based methods by means of 2‐DE and MS and a gel‐free approach via LC‐MS/MS. Among the identified 785 proteins, synthesis of around 100 conserved hypothetical proteins could be confirmed. Membrane proteins were detected at a higher rate in the gel‐free than in the gel‐based approach. The abundance of proteins in the constructed proteome reference map was analyzed and the 30 most abundant proteins were determined. The reference map was then used as a starting point to characterize the regulon under control of the response regulator PilR. PilR is part of the two‐component regulatory system PilSR controlling type IV pilin gene ( pilAB ) expression in strain BH72, which was strongly decreased (19.7‐fold) in the pilR ‐mutant. Changes of protein composition in the wild type and the regulatory mutant were compared by the gel‐based and gel‐free analyses. Proteins responsible for amino acid and energy metabolism, chaperones as well as proteins that are involved in iron metabolism and iron storage were present in a pilR ‐mutant at different levels than in the wild‐type strain. Levels of the transcriptional regulator Flp were also dependent on PilR, indicating that PilR might be part of a hierarchical regulatory cascade.