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Unusual Binding of a Potential Biomarker with Human Serum Albumin
Author(s) -
De Dipanwita,
Kaur Harpreet,
Datta Anindya
Publication year - 2013
Publication title -
chemistry – an asian journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.18
H-Index - 106
eISSN - 1861-471X
pISSN - 1861-4728
DOI - 10.1002/asia.201201060
Subject(s) - chemistry , human serum albumin , binding site , fluorescence , docking (animal) , quenching (fluorescence) , stereochemistry , serum albumin , biophysics , biochemistry , biology , medicine , physics , nursing , quantum mechanics
This study investigates the specific binding of a potential biomarker, [2,2′‐bipyridyl]‐3,3′‐diol (BP(OH) 2 ), with human serum albumin (HSA). The binding of BP(OH) 2 at the two primary drug‐binding sites on HSA (Sudlow′s sites I and II) is explored by a competitive‐binding study and monitored by considering the green‐light emission from its diketo tautomer. Warfarin is used as a marker for site I and dansyl‐ L ‐proline (DP) as a competitor for site II. Steady‐state and time‐resolved fluorescence measurements affirm that neither of Sudlow′s sites is the binding locus of BP(OH) 2 . To gain an idea regarding the probable binding site of BP(OH) 2 , we perform molecular‐docking studies, which reveal a close proximity of the probe to Trp‐214 in subdomain IIA of HSA. Confirmation of this contention is achieved by studying the quenching of the fluorescence of Trp‐214 in the presence of BP(OH) 2 . Moreover, static quenching seems to be responsible for the depletion of the fluorescence of Trp‐214, as manifested by the invariance of the intrinsic fluorescence lifetime of Trp‐214, as a function of the concentration of BP(OH) 2 . Based on displacement and quenching studies, supported by molecular docking, we propose that BP(OH) 2 binds in a cleft that separates subdomains IIIA and IIB, which is in close proximity to Trp‐214.