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MOMP (major outer membrane protein) of Campylobacter jejuni ; a versatile pore‐forming protein
Author(s) -
Dé Emmanuelle,
Jullien Magali,
Labesse Gilles,
Pagès Jean Marie,
Molle Gérard,
Bolla Jean Michel
Publication year - 2000
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(00)01244-8
Subject(s) - trimer , monomer , porin , oligomer , chemistry , campylobacter jejuni , cationic polymerization , conductance , membrane , biophysics , crystallography , bacterial outer membrane , polymer chemistry , dimer , polymer , bacteria , biochemistry , organic chemistry , escherichia coli , biology , genetics , mathematics , gene , combinatorics
The great majority of trimeric porins of Gram‐negative bacteria cannot be dissociated into monomers without disrupting their folded conformation. The porin of Campylobacter jejuni , however, displays two folded structures, a classical oligomer and a monomer resistant to detergent denaturation. We probed the transition of trimer to monomer using light scattering experiments and examined the secondary structures of these two molecular states by infra‐red spectroscopy. The channel‐forming properties of both trimer and monomer were studied after incorporation into artificial lipid bilayers. In these conditions, the trimer induced ion channels with a conductance value of 1200 pS in 1 M NaCl. The pores showed marked cationic selectivity and sensitivity to low voltage. Analysis of the isolated monomer showed nearly the same single‐channel conductance and the same selectivity and sensitivity to voltage. These results indicate that the folded monomer form of C. jejuni MOMP displays essentially the same pore‐forming properties as the native trimer.