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A new subfamily of bacterial ABC‐type transport systems catalyzing export of drugs and carbohydrates
Author(s) -
Reizer Jonathan,
Reizer Aiala,
Saier Milton H.
Publication year - 1992
Publication title -
protein science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.353
H-Index - 175
eISSN - 1469-896X
pISSN - 0961-8368
DOI - 10.1002/pro.5560011012
Subject(s) - subfamily , chemistry , biochemistry , stereochemistry , combinatorial chemistry , gene
Sequence comparison studies revealed that the drug resistance transporter of Streptomyces peucetius (DrrAB) and two nodulation gene products (NodIJ) of Rhizobium leguminosarum are homologous to proteins encoded by three sets of genes that comprise capsular polysaccharide export systems in gram‐negative bacteria: KpsTM of Escherichia coli , BexABC of Haemophilus influenzae , and CtrDCB of Neisseria meningitidis. These five systems comprise a new subfamily within the family of ATP binding cassette (ABC)‐type transporters. We have termed this subfamily the ABC‐2 subfamily. For three of the systems comprising this subfamily (Drr, Nod, and Kps) only one integral membrane constituent has been identified, whereas for the other two systems (Bex and Ctr) two dissimilar integral membrane constituents have been found. This observation suggests that the transmembrane channels of ABC‐2‐type transporters can be formed of homo‐ or heterooligomers as is true of several other classes of transport systems.