Linked Life Data

9675263

Source:http://linkedlifedata.com/resource/pubmed/id/9675263

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
1998-9-9
pubmed:abstractText
Structural and conformational changes in tear lipocalins were detected in association with ligand binding and release. Circular dichroism measurements demonstrated that ligand binding induces beta structure formation, aromatic side chain asymmetry, and a more rigid state in tear lipocalins (TL). The exposure of the tyrosyl component is less in apo-TL than in holo-TL. The sole tryptophan residue, Trp17, is buried in both holo- and apo-TL. The steady state exposure of Trp17 is the same in holo- and apo-TL, but the dynamic exposure is two-fold greater in apo-TL. Maneuvers to unfold the protein with urea or incubation in an acidic environment resulted in increased exposure of aromatic amino acids. Electron paramagnetic resonance studies verified that lipids are liberated from TL in an acidic environment. Acidic pH promotes conformational changes in TL involving aromatic residues, particularly the conserved residue Trp17. These changes are associated with lipid release. The liberation of lipid from the cavity of TL under acidic conditions involves a molten globule state of the protein. We postulate that TL, exposed to the steep surface pH gradient that exists at lipid-aqueous interfaces, would release lipid in association with a molten globule transition. The data suggest a plausible regulatory mechanism for lipid delivery from lipocalins at the tear film surface.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jul
pubmed:issn
0006-3002
pubmed:author
pubmed:issnType
Print
pubmed:day
28
pubmed:volume
1386
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
145-56
pubmed:dateRevised
2007-11-15
pubmed:meshHeading
pubmed:year
1998
pubmed:articleTitle
Structural changes in human tear lipocalins associated with lipid binding.
pubmed:affiliation
Departments of Pathology and Ophthalmology, UCLA School of Medicine, 100 Stein Plaza, Los Angeles, CA 90095, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't