Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
2004-5-11
pubmed:databankReference
pubmed:abstractText
The thermoacidophilic gram-positive bacterium Alicyclobacillus acidocaldarius grows at 60 degrees C and pH 2-3. The organism can utilize maltose and maltodextrins as energy source that are taken up by an ATP-binding cassette (ABC) import system. Genes encoding a maltose binding protein, MalE, and two membrane-integral subunits, MalF and MalG, are clustered on the chromosome but a malK gene translating into a cognate ATPase subunit is lacking. Here we report the cloning of malK from genomic DNA by using the msiK gene of Streptomyces lividans as a probe. Purified MalK exhibited a spontaneous ATPase activity with a Vmax of 0.13 micromol Pi/min/mg and a Km of 330 microM that was optimal at the growth temperature of the organism. Coexpression of malK, malF and malG in Escherichia coli resulted in the formation of a complex that could be coeluted from an affinity matrix after solubilization of membranes with dodecylmaltoside. Proteoliposomes prepared from the MalFGK complex and preformed phospholipid vesicles of A. acidocaldarius displayed a low intrinsic ATPase activity that was stimulated sevenfold by maltose-loaded MalE, thereby indicating coupling of ATP hydrolysis to substrate translocation. These results provide evidence for MalK being the physiological ATPase subunit of the A. acidocaldarius maltose transporter. Moreover, to our knowledge, this is the first report on the functional reconstitution of an ABC transport system from a thermophilic microorganism.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
http://linkedlifedata.com/resource/pubmed/chemical/ATP-Binding Cassette Transporters, http://linkedlifedata.com/resource/pubmed/chemical/Archaeal Proteins, http://linkedlifedata.com/resource/pubmed/chemical/Bacterial Proteins, http://linkedlifedata.com/resource/pubmed/chemical/Carbon, http://linkedlifedata.com/resource/pubmed/chemical/Escherichia coli Proteins, http://linkedlifedata.com/resource/pubmed/chemical/Macromolecular Substances, http://linkedlifedata.com/resource/pubmed/chemical/MalF protein, E coli, http://linkedlifedata.com/resource/pubmed/chemical/MalG protein, Thermococcus litoralis, http://linkedlifedata.com/resource/pubmed/chemical/MalK protein, Bacteria, http://linkedlifedata.com/resource/pubmed/chemical/MalK protein, E coli, http://linkedlifedata.com/resource/pubmed/chemical/Monosaccharide Transport Proteins, http://linkedlifedata.com/resource/pubmed/chemical/Proteolipids, http://linkedlifedata.com/resource/pubmed/chemical/proteoliposomes
pubmed:status
MEDLINE
pubmed:month
May
pubmed:issn
0006-3002
pubmed:author
pubmed:copyrightInfo
Copyright 2004 Elsevier B.V.
pubmed:issnType
Print
pubmed:day
12
pubmed:volume
1656
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
57-65
pubmed:dateRevised
2009-1-10
pubmed:meshHeading
pubmed:year
2004
pubmed:articleTitle
Functional reconstitution of a maltose ATP-binding cassette transporter from the thermoacidophilic gram-positive bacterium Alicyclobacillus acidocaldarius.
pubmed:affiliation
Institut für Biologie, Humboldt Universität zu Berlin, Bakterienphysiologie, Chausseestr. 117, D-10115 Berlin, Germany.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't