Linked Life Data

11425849

Source:http://linkedlifedata.com/resource/pubmed/id/11425849

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
37
pubmed:dateCreated
2001-9-10
pubmed:abstractText
Zn-alpha(2)-glycoprotein (ZAG) is a member of the major histocompatibility complex (MHC) class I family of proteins and is identical in amino acid sequence to a tumor-derived lipid-mobilizing factor associated with cachexia in cancer patients. ZAG is present in plasma and other body fluids, and its natural function, like leptin's, probably lies in lipid store homeostasis. X-ray crystallography has revealed an open groove between the helices of ZAG's alpha(1) and alpha(2) domains, containing an unidentified small ligand in a position similar to that of peptides in MHC proteins (Sanchez, L. M., Chirino, A. J., and Bjorkman, P. J. (1999) Science 283, 1914-1919). Here we show, using serum-derived and bacterial recombinant protein, that ZAG binds the fluorophore-tagged fatty acid 11-(dansylamino)undecanoic acid (DAUDA) and, by competition, natural fatty acids such as arachidonic, linolenic, eicosapentaenoic, and docosahexaenoic acids. Other MHC class I-related proteins (FcRn, HFE, HLA-Cw*0702) showed no such evidence of binding. Fluorescence and isothermal calorimetry analysis showed that ZAG binds DAUDA with K(d) in the micromolar range, and differential scanning calorimetry showed that ligand binding increases the thermal stability of the protein. Addition of fatty acids to ZAG alters its intrinsic (tryptophan) fluorescence emission spectrum, providing a strong indication that ligand binds in the expected position close to a cluster of exposed tryptophan side chains in the groove. This study therefore shows that ZAG binds small hydrophobic ligands, that the natural ligand may be a polyunsaturated fatty acid, and provides a fluorescence-based method for investigating ZAG-ligand interactions.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Sep
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
14
pubmed:volume
276
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
35008-13
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
2001
pubmed:articleTitle
Hydrophobic ligand binding by Zn-alpha 2-glycoprotein, a soluble fat-depleting factor related to major histocompatibility complex proteins.
pubmed:affiliation
Division of Environmental and Evolutionary Biology, Institute of Biomedical and Life Sciences and the Department of Chemistry, University of Glasgow, Glasgow G12 8QQ, United Kingdom. malcolm.kennedy@bio.gla.ac.uk
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, Non-P.H.S., Research Support, Non-U.S. Gov't