TY - JOUR
T1 - Novel 7-(dimethylamino)fluorene-based fluorescent probes and their binding to human serum albumin
AU - Park, Kwanghee Koh
AU - Park, Joon Woo
AU - Hamilton, Andrew D.
PY - 2009
Y1 - 2009
N2 - A novel solvatochromic fluorescent molecule, 9,9-dibutyl-7-(dimethylamino)- 2-fluorenesulfonate 2 was synthesized from 2-nitrofluorene in moderate yield. The fluorescence spectra of 2 and 7-(dimethylamino)-2-fluorenesulfonate 1 shift to shorter wavelengths as the polarity of the medium decreases. Both 1 and 2 bind to hydrophobic sites of human serum albumin (HSA). The apparent binding constants were determined by fluorescence titration to be 0.37 × 10 6 M-1 for 1 and 2.2 × 106 M-1 for 2. The energy of the Trp-214 fluorescence of HSA is transferred to the HSA-bound fluorophores with near 100% efficiency. The covalent bonding of acrylodan (AC) to Cys-34 has little effect on the binding affinity of 2 to HSA or fluorescent behavior of HSA-bound 2. Bound 2 also has little effect on the fluorescence of AC, but 2→AC and Trp-214→2→AC resonance energy transfers were observed. Competitive binding between the fluorene compounds and other ligands such as 1-anilino-8-naphthalenesulfonate, aspirin, S-(+)-ibuprofen and phenylbutazone were also studied fluorometrically. The results indicated that the primary binding site of 2 to HSA is site II in domain IIIA, whereas 1 binds to site I in domain IIA, but a different region from the phenylbutazone binding site. Because of its large molar absorptivity, strong fluorescence, sensitivity to its environment, and high binding constant to HSA, 2 can be used successfully in the study of proteins and their binding properties.
AB - A novel solvatochromic fluorescent molecule, 9,9-dibutyl-7-(dimethylamino)- 2-fluorenesulfonate 2 was synthesized from 2-nitrofluorene in moderate yield. The fluorescence spectra of 2 and 7-(dimethylamino)-2-fluorenesulfonate 1 shift to shorter wavelengths as the polarity of the medium decreases. Both 1 and 2 bind to hydrophobic sites of human serum albumin (HSA). The apparent binding constants were determined by fluorescence titration to be 0.37 × 10 6 M-1 for 1 and 2.2 × 106 M-1 for 2. The energy of the Trp-214 fluorescence of HSA is transferred to the HSA-bound fluorophores with near 100% efficiency. The covalent bonding of acrylodan (AC) to Cys-34 has little effect on the binding affinity of 2 to HSA or fluorescent behavior of HSA-bound 2. Bound 2 also has little effect on the fluorescence of AC, but 2→AC and Trp-214→2→AC resonance energy transfers were observed. Competitive binding between the fluorene compounds and other ligands such as 1-anilino-8-naphthalenesulfonate, aspirin, S-(+)-ibuprofen and phenylbutazone were also studied fluorometrically. The results indicated that the primary binding site of 2 to HSA is site II in domain IIIA, whereas 1 binds to site I in domain IIA, but a different region from the phenylbutazone binding site. Because of its large molar absorptivity, strong fluorescence, sensitivity to its environment, and high binding constant to HSA, 2 can be used successfully in the study of proteins and their binding properties.
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U2 - 10.1039/b911605b
DO - 10.1039/b911605b
M3 - Article
C2 - 19795061
AN - SCOPUS:70349835638
SN - 1477-0520
VL - 7
SP - 4225
EP - 4232
JO - Organic and Biomolecular Chemistry
JF - Organic and Biomolecular Chemistry
IS - 20
ER -