Linked Life Data

12418892

Source:http://linkedlifedata.com/resource/pubmed/id/12418892

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
45
pubmed:dateCreated
2002-11-6
pubmed:abstractText
Marinobactins are a class of newly discovered marine bacterial siderophores with a unique amphiphilic structure, suggesting that their functions relate to interactions with cell membranes. Here we use small and large unilamellar L-alpha-dimyristoylphosphatidylcholine vesicles (SUVs and LUVs) as model membranes to examine the thermodynamics and kinetics of the membrane binding of marinobactins, particularly marinobactin E (apo-M(E)) and its iron(III) complex, Fe-M(E). Siderophore-membrane interactions are characterized by NMR line broadening, stopped-flow spectrophotometry, fluorescence quenching, and ultracentrifugation. It is determined that apo-M(E) has a strong affinity for lipid membranes with molar fraction partition coefficients K(x)()(apo)(-)(M)E = 6.3 x 10(5) for SUVs and 3.6 x 10(5) for LUVs. This membrane association is shown to cause only a 2-fold decrease in the rate of iron(III) binding by apo-M(E). However, upon the formation of the iron(III) complex Fe-M(E), the membrane affinity of the siderophore decreased substantially (K(x)()(Fe)(-)(M)E = 1.3 x 10(4) for SUVs and 9.6 x 10(3) for LUVs). The kinetics of membrane binding and dissociation by Fe-M(E) were also determined (k(on)(Fe)(-)(M)E = 1.01 M(-)(1) s(-)(1); k(off)(Fe)(-)(M)E = 4.4 x 10(-)(3) s(-)(1)). The suite of marinobactins with different fatty acid chain lengths and degrees of chain unsaturation showed a range of membrane affinities (5.8 x 10(3) to 36 M(-)(1)). The affinity that marinobactins exhibit for membranes and the changes observed upon iron binding could provide unique biological advantages in a receptor-assisted iron acquisition process in which loss of the iron-free siderophore by diffusion is limited by the strong association with the lipid phase.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Nov
pubmed:issn
0002-7863
pubmed:author
pubmed:issnType
Print
pubmed:day
13
pubmed:volume
124
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
13408-15
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
2002
pubmed:articleTitle
Membrane affinity of the amphiphilic marinobactin siderophores.
pubmed:affiliation
Department of Chemistry, Princeton University, New Jersey 08544, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, U.S. Gov't, Non-P.H.S., Research Support, Non-U.S. Gov't