The location of the high- and low-affinity bilirubin-binding sites on serum albumin: ligand-competition analysis investigated by circular dichroism
Jazyk angličtina Země Nizozemsko Médium print-electronic
Typ dokumentu časopisecké články, práce podpořená grantem
PubMed
23838624
DOI
10.1016/j.bpc.2013.06.004
PII: S0301-4622(13)00093-8
Knihovny.cz E-zdroje
- Klíčová slova
- BR, BSA, Bilirubin, Binding site, CD, GS, HSA, High affinity, Ibf, Ligand-completion, Low affinity, PSB, RSA, RbSA, SA, SSA, Stereoselectivity, bilirubin, bovine serum albumin, circular dichroism, dCD, difference circular dichroism, gossypol, human serum albumin, ibuprofen, phosphate saline buffer, rabbit serum albumin, rat serum albumin, serum albumin, sheep serum albumin,
- MeSH
- aminokyselinové motivy MeSH
- bilirubin chemie metabolismus MeSH
- cirkulární dichroismus MeSH
- hemin chemie metabolismus MeSH
- ibuprofen chemie metabolismus MeSH
- králíci MeSH
- krysa rodu Rattus MeSH
- lidé MeSH
- ligandy * MeSH
- molekulární konformace MeSH
- ovce MeSH
- sérový albumin chemie metabolismus MeSH
- simulace molekulového dockingu MeSH
- skot MeSH
- terciární struktura proteinů MeSH
- vazba proteinů MeSH
- vazebná místa MeSH
- zvířata MeSH
- Check Tag
- králíci MeSH
- krysa rodu Rattus MeSH
- lidé MeSH
- skot MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- bilirubin MeSH
- hemin MeSH
- ibuprofen MeSH
- ligandy * MeSH
- sérový albumin MeSH
The locations of three bilirubin (BR)-binding sites with different affinities were identified as subdomains IB, IIA and IIIA for five mammalian serum albumins (SAs): human (HSA), bovine (BSA), rat, (RSA), rabbit (RbSA) and sheep (SSA). The stereoselectivity of a high-affinity BR-binding site was identified in the BR/SA=1/1 system by circular dichroism (CD) spectroscopy, the sites with low affinity to BR were analyzed using difference CD. Site-specific ligand-competition experiments with ibuprofen (marker for subdomain IIIA) and hemin (marker for subdomain IB) did not reveal any changes for the BR/SA=1/1 system and showed a decrease of the bound BR at BR/SA=3/1. Both sites were identified as sites with low affinity to BR. The correlation between stereoselectivity and the arrangement of Arg-Lys residues indicated similarity between the BR-binding sites in subdomain IIIA for all of the SAs studied. Subdomain IB in HSA, BSA, SSA and RbSA has P-stereoselectivity while in RSA it has M-selectivity toward BR. A ligand-competition experiment with gossypol shows a decrease of the CD signal of bound BR for the BR/SA=1/1 system as well as for BR/SA=3/1. Subdomain IIA was assigned as a high-affinity BR-binding site. The P-stereoselectivity of this site in HSA (and RSA, RbSA) was caused by the right-hand localization of charged residues R257/R218-R222, whereas the left-hand orientation of R257/R218-R199 led to the M-stereoselectivity of the primary binding site in BSA (and SSA).
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