Linked Life Data

8344918

Source:http://linkedlifedata.com/resource/pubmed/id/8344918

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
22
pubmed:dateCreated
1993-9-7
pubmed:abstractText
TonB, a cytoplasmic membrane protein, couples cytoplasmic membrane protonmotive force to active transport across the outer membrane of Escherichia coli. In vivo cross-linking studies were initiated to analyze TonB interactions with other cell envelope proteins. Four TonB-specific cross-linked complexes were detected with apparent molecular masses of 195, 77, 59, and 43.5 kDa. The 195-kDa complex was shown to contain both TonB and FepA, the outer membrane receptor for the siderophore enterochelin. The 195-kDa complex is absent in strains missing either TonB or FepA and can be detected by either TonB-specific or FepA-specific monoclonal antibodies. This is the first direct in vivo evidence that TonB can span the periplasmic space to interact physically with outer membrane receptors. Consistent with that observation, the outer membrane protease OmpT was shown to play a role in TonB turnover, both in the presence and absence of ExbB results in the rapid degradation of TonB. The absence of OmpT could be used to stabilize TonB in an exbB::Tn10 strain such that steady state levels of TonB protein are identical to a wild-type strain. Under those conditions, the absence of ExbB results in greatly reduced TonB activity, indicating that ExbB plays a direct role in energy transduction and probably secondarily protects TonB protein from proteolysis. The 59-kDa complex was absent in an exbB::Tn10 strain, suggesting either that ExbB is in the complex with TonB or that ExbB is required to form the 59-kDa complex. A tolQ nonsense mutation had no effect on the cross-linking profile observed, confirming that its participation in TonB-dependent phenomena is minor and most likely the result of evolutionary cross-talk.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
http://linkedlifedata.com/resource/pubmed/chemical/Bacterial Outer Membrane Proteins, http://linkedlifedata.com/resource/pubmed/chemical/Bacterial Proteins, http://linkedlifedata.com/resource/pubmed/chemical/Carrier Proteins, http://linkedlifedata.com/resource/pubmed/chemical/Cross-Linking Reagents, http://linkedlifedata.com/resource/pubmed/chemical/Escherichia coli Proteins, http://linkedlifedata.com/resource/pubmed/chemical/Formaldehyde, http://linkedlifedata.com/resource/pubmed/chemical/Membrane Proteins, http://linkedlifedata.com/resource/pubmed/chemical/Receptors, Cell Surface, http://linkedlifedata.com/resource/pubmed/chemical/enterobactin receptor, http://linkedlifedata.com/resource/pubmed/chemical/tonB protein, Bacteria, http://linkedlifedata.com/resource/pubmed/chemical/tonB protein, E coli
pubmed:status
MEDLINE
pubmed:month
Aug
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
5
pubmed:volume
268
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
16302-8
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1993
pubmed:articleTitle
Energy transduction between membranes. TonB, a cytoplasmic membrane protein, can be chemically cross-linked in vivo to the outer membrane receptor FepA.
pubmed:affiliation
Department of Microbiology, Washington State University, Pullman 99164.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, U.S. Gov't, Non-P.H.S.