Open AccessDemonstration of a folded monomeric form of porin PhoE of Escherichia coli in vivo
Author(s) -
Patrick Van Gelder,
Jan Tommassen
Publication year - 1996
Publication title -
journal of bacteriology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.652
H-Index - 246
eISSN - 1067-8832
pISSN - 0021-9193
DOI - 10.1128/jb.178.17.5320-5322.1996
Subject(s) - porin , trimer , biology , bacterial outer membrane , monomer , escherichia coli , biochemistry , biophysics , folding (dsp implementation) , protein subunit , protein folding , dimer , chemistry , organic chemistry , electrical engineering , gene , engineering , polymer
The porins in the outer membranes of gram-negative bacteria are trimeric proteins. A folded monomeric form of the Escherichia coli porin PhoE, with a higher electrophoretic mobility than that of the denatured protein, has recently been detected in in vitro folding studies. To investigate the possible biological significance of the folded monomer, we attempted to detect this form in vivo. After pulse-labeling, folded monomers could be detected by immunoprecipitation. Furthermore, folded monomers were detected in a preparation of mutant PhoE porins, in which the subunit interactions were weakened by a E-66-->R substitution. Together, these results show that the folded monomer is not an in vitro folding artifact but an integral part of the native trimer.