Dual-Sensor Fluorescent Probes of Surfactant-Induced Unfolding of Human Serum Albumin

Abstract

Two extrinsic fluorescent probes, 3-(dimethylamino)-8,9,10,11-tetrahydro-7H-cyclohepta[a]naphthalen-7-one (1) and 7-(dimethylamino)-2,3-dihydrophenanthren-4(1H)-one (2), are used to probe the unfolding of human serum albumin by sodium dodecyl sulfate (SDS). These probes respond separately to the polarity and H-bond donating ability of their surroundings. Competitive binding experiments show that flurophore 1 binds to site I (domain IIA) and 2 binds to site II (domain IIIA). The local acidity of 1 in site I is out of the sensing range of 1, whereas the local acidity of 2 in site II is calculated to be nearly zero on Catalan’s solvent acidity index. Both probes show that the first two equivalents of bound SDS result in a decrease in the local polarity of the binding sites. Each subsequent equivalent of SDS gives rise to a dramatic increase in polarity until HSA is saturated with seven molecules of SDS at the end of the specific binding domain. Compound 2 experiences an increase of acidity of 0.10 on Catalan’s solvent acidity index through seven equivalents of SDS, but the local acidity for 1 is still out of range. The increase in acidity experienced by 2 is greater than the increase in polarity. This result is consistent with greater exposure of the carbonyl group in 2, but not the bulk of 2, to the aqueous solvent in site II of the SDS-saturated HSA complex.

Nanostructured Luminescent Micelles: Efficient “Functional Materials” for Sensing Nitroaromatic and Nitramine Explosives

“…Considering the advancement of nanotechnology and nanoscience, nanostructured micellar probes have been considered as a promising candidate for bio-sensing owing to their structural flexibility and versatility [62]. However, only a handful of luminescent biosensor probes based on micellar systems appeared in the recent literature [16][17][18][19][20][63][64][65][66][67][68][69][70][71][72][73][74]. We will provide a very brief glimpse on these luminescent biosensors, which are used to create self-assembled nanostructure materials showing promise for use as next generation potential as "functional materials".…”

A ‘turn‐on’ fluorescent chemosensor for quantification of serum albumin in aqueous solution at neutral pH

“…Therefore, the electrostatic interaction could not be considered as the binding modes between 1 and BSA. Meanwhile, because BSA and HSA are typical proteins with several hydrophobic pockets , the binding mode between 1 and BSA could possibly result from hydrophobic interactions, which may be the primary cause for the selectivity of 1 for BSA and HSA.…”

“…Therefore, the electrostatic interaction could not be considered as the binding modes between 1 and BSA. Meanwhile, because BSA and HSA are typical proteins with several hydrophobic pockets (33)(34)(35), the binding mode between 1 and BSA could possibly result from hydrophobic interactions, which may be the primary cause for the selectivity of 1 for BSA and HSA. Generally, hydrophobic interactions (ΔH > 0, ΔS > 0), hydrogen bonds (ΔH < 0, ΔS < 0), Van der Waals forces (ΔH < 0, ΔS < 0) and electrostatic interactions (ΔH < 0, ΔS > 0) may all play potential roles in the noncovalent interactions between chromophores and serum albumin (4,18,36).…”

The electronic origin of the ground state spectral features and excited state deactivation in cycloalkanones: the role of intermolecular H-bonding in neat and binary mixtures of solvents

“…However, in the MeOH-H 2 O system the quenching does not follow the simple straight-line equation but rather gives an upward curving plot because of the involvement of quenchers. Moreover, the diminished emission intensity is probably caused by opening some deactivation channel, such as ISC by complexation with the carbonyl motif [42,43,44].…”