Open AccessPurification and characterization of LPS‐free porins isolated from Salmonella minnesota
Author(s) -
Latsch Maria,
Stemmer Friedrich,
Loos Michael
Publication year - 1992
Publication title -
fems microbiology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.899
H-Index - 151
eISSN - 1574-6968
pISSN - 0378-1097
DOI - 10.1111/j.1574-6968.1992.tb05166.x
Subject(s) - porin , chromatofocusing , bacterial outer membrane , chemistry , monomer , chromatography , biochemistry , bacteria , size exclusion chromatography , microbiology and biotechnology , biology , escherichia coli , enzyme , organic chemistry , gene , polymer , genetics
Porins of Salmonella minnesota , R595, were purified by anion exchange chromatography and subsequently isolated in their monomeric form by chromatofocusing. Two forms of porin could be isolated, both with an apparent molecular mass of 37 000, but of differing isolelectric points (p I 4.6 versus p I of 4.9). Porins with p I 4.9 did not contain any detectable LPS, but porins with p I 4.6 were found to contain trace amounts of LPS (1.3 × 10 −4 μg LPS/1 μg porin) as measured using a highly sensitive limulus assay. Unlike the LPS‐associated porins the monomeric porins were biologically inert with regard to pore formation, but they were still able to bind C1q, a subcomponent of the first component of complement.