Linked Life Data

8316079

Source:http://linkedlifedata.com/resource/pubmed/id/8316079

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
1993-7-23
pubmed:abstractText
Escherichia coli possesses two energy-coupled import systems through which substances of low concentration and of a size too large to permit diffusion through the porins are translocated across the outer membrane. Group B colicins, ferric siderophores and vitamin B12 are taken up via the TonB-ExbB-ExbD, group A colicins via the TolA-TolQ-TolR system. Cross-complementation between the two systems was demonstrated in that tolQ tolR mutants transformed with plasmids carrying exbB exbD became sensitive to group A colicins, and exbB exbD mutants transformed with plasmid-encoded tolQ tolR became sensitive to group B colicins. TolQ-TolR interacted through TonB, and ExbB-ExbD interacted through TolA with the outer membrane receptors and colicins. Activity of ExbB ExbD via TolA was higher in cells lacking TonB, and activity of TolQ TolR via TonB was increased when TolA was missing. The very distinct TolA and TonB proteins mediate exclusive interaction with group A and group B receptors, respectively. ExbB-TolR and ExbD-TolQ mixtures showed little if any complementation of exbB exbD and tolQ tolR mutants indicating coevolution of ExbB with ExbD and TolQ with TolR. Sequence homology and mutual functional substitution of ExbB-ExbD and TolQ-TolR suggest the evolution of the two import systems from a single import system.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
http://linkedlifedata.com/resource/pubmed/chemical/Bacterial Proteins, http://linkedlifedata.com/resource/pubmed/chemical/Colicins, http://linkedlifedata.com/resource/pubmed/chemical/Escherichia coli Proteins, http://linkedlifedata.com/resource/pubmed/chemical/ExbB protein, E coli, http://linkedlifedata.com/resource/pubmed/chemical/Ferrichrome, http://linkedlifedata.com/resource/pubmed/chemical/Membrane Proteins, http://linkedlifedata.com/resource/pubmed/chemical/Recombinant Fusion Proteins, http://linkedlifedata.com/resource/pubmed/chemical/albomycin, http://linkedlifedata.com/resource/pubmed/chemical/exbD protein, E coli, http://linkedlifedata.com/resource/pubmed/chemical/tolA protein, E coli, http://linkedlifedata.com/resource/pubmed/chemical/tolQ protein, E coli, http://linkedlifedata.com/resource/pubmed/chemical/tolR protein, E coli, http://linkedlifedata.com/resource/pubmed/chemical/tonB protein, Bacteria, http://linkedlifedata.com/resource/pubmed/chemical/tonB protein, E coli
pubmed:status
MEDLINE
pubmed:month
Apr
pubmed:issn
0950-382X
pubmed:author
pubmed:issnType
Print
pubmed:volume
8
pubmed:geneSymbol
exbB, exbD, tolA, tolQ, tolR, tonB
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
261-8
pubmed:dateRevised
2010-11-18
pubmed:meshHeading
pubmed:year
1993
pubmed:articleTitle
Evolutionary relationship of uptake systems for biopolymers in Escherichia coli: cross-complementation between the TonB-ExbB-ExbD and the TolA-TolQ-TolR proteins.
pubmed:affiliation
Mikrobiologie II, Universität Tübingen, Germany.
pubmed:publicationType
Journal Article, Comparative Study, Research Support, Non-U.S. Gov't