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Rosin Surfactant QRMAE Can Be Utilized as an Amorphous Aggregate Inducer: A Case Study of Mammalian Serum Albumin.

Ishtikhar M, Chandel TI, Ahmad A, Ali MS, Al-Lohadan HA, Atta AM, Khan RH - PLoS ONE (2015)

Bottom Line: It was observed that a suitable molar ratio of protein to QRMAE surfactant enthusiastically induces amorphous aggregate formation at a pH above two units of pI.Rosin surfactant QRMAE-albumins interactions revealed a unique interplay between the initial electrostatic and the subsequent hydrophobic interactions that play an important role towards the formation of hydrophobic interactions-driven amorphous aggregate.Amorphous aggregation of proteins is associated with varying diseases, from the formation of protein wine haze to the expansion of the eye lenses in cataract, during the expression and purification of recombinant proteins.

View Article: PubMed Central - PubMed

Affiliation: Protein Biophysics Laboratory, Interdisciplinary Biotechnology Unit, Aligarh Muslim University, Aligarh - 202002, India.

ABSTRACT
Quaternary amine of diethylaminoethyl rosin ester (QRMAE), chemically synthesized biocompatible rosin based cationic surfactant, has various biological applications including its use as a food product additive. In this study, we examined the amorphous aggregation behavior of mammalian serum albumins at pH 7.5, i.e., two units above their isoelectric points (pI ~5.5), and the roles played by positive charge and hydrophobicity of exogenously added rosin surfactant QRMAE. The study was carried out on five mammalian serum albumins, using various spectroscopic methods, dye binding assay, circular dichroism and electron microscopy. The thermodynamics of the binding of mammalian serum albumins to cationic rosin modified surfactant were established using isothermal titration calorimetry (ITC). It was observed that a suitable molar ratio of protein to QRMAE surfactant enthusiastically induces amorphous aggregate formation at a pH above two units of pI. Rosin surfactant QRMAE-albumins interactions revealed a unique interplay between the initial electrostatic and the subsequent hydrophobic interactions that play an important role towards the formation of hydrophobic interactions-driven amorphous aggregate. Amorphous aggregation of proteins is associated with varying diseases, from the formation of protein wine haze to the expansion of the eye lenses in cataract, during the expression and purification of recombinant proteins. This study can be used for the design of novel biomolecules or drugs with the ability to neutralize factor(s) responsible for the aggregate formation, in addition to various other industrial applications.

No MeSH data available.


Related in: MedlinePlus

(A) ANS fluorescence spectra of mammalian serum albumins in the abscence and presence of QRMAE at pH above two unit of their pI and (B) ANS fluorescence intensity data of protein samples at 480 nm in the absence and presence of QRMAE at pH below and above two unit of their pI.
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pone.0139027.g003: (A) ANS fluorescence spectra of mammalian serum albumins in the abscence and presence of QRMAE at pH above two unit of their pI and (B) ANS fluorescence intensity data of protein samples at 480 nm in the absence and presence of QRMAE at pH below and above two unit of their pI.

Mentions: 1-Anilino-8-napthalene sulfonic acid, is an ammonium salt widely used to characterize the nature of the protein aggregates. ANS binds with an amorphous aggregate and shows enhanced fluorescence intensity upon binding with aggregated particles in the protein samples. The protein samples were incubated at 65°C for an hour and then incorporated with ANS. Fluorescence spectra of QRMAE alone and the controls samples were found to be negligible at pH below two unit of pI, whereas, on the other hand, QRMAE-induced aggregation of mammalian serum albumins with ANS showed a characteristic high intensity spectra at pH above two unit of pI (Fig 3A), which suggested a binding of ANS with the amorphous or amyloid aggregates. ANS fluorescence intensities, measured at 480 nm after excitation at 380 nm, showed a negligible effect at pH below two units of their pI (Fig 3B). However, there is a significant difference in the fluorescence intensities between the protein samples above two units of its pI and the sample when incubated with QRMAE under pH below two unit of its pI. As shown in Fig 3 and Table 1; the fluorescence intensity obtained by the controls was very low, but when the protein was incubated with QRMAE above two units of its pI, there was an elevation in the intensities, approximately up to three-folds at 480 nm.


Rosin Surfactant QRMAE Can Be Utilized as an Amorphous Aggregate Inducer: A Case Study of Mammalian Serum Albumin.

Ishtikhar M, Chandel TI, Ahmad A, Ali MS, Al-Lohadan HA, Atta AM, Khan RH - PLoS ONE (2015)

(A) ANS fluorescence spectra of mammalian serum albumins in the abscence and presence of QRMAE at pH above two unit of their pI and (B) ANS fluorescence intensity data of protein samples at 480 nm in the absence and presence of QRMAE at pH below and above two unit of their pI.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4587963&req=5

pone.0139027.g003: (A) ANS fluorescence spectra of mammalian serum albumins in the abscence and presence of QRMAE at pH above two unit of their pI and (B) ANS fluorescence intensity data of protein samples at 480 nm in the absence and presence of QRMAE at pH below and above two unit of their pI.
Mentions: 1-Anilino-8-napthalene sulfonic acid, is an ammonium salt widely used to characterize the nature of the protein aggregates. ANS binds with an amorphous aggregate and shows enhanced fluorescence intensity upon binding with aggregated particles in the protein samples. The protein samples were incubated at 65°C for an hour and then incorporated with ANS. Fluorescence spectra of QRMAE alone and the controls samples were found to be negligible at pH below two unit of pI, whereas, on the other hand, QRMAE-induced aggregation of mammalian serum albumins with ANS showed a characteristic high intensity spectra at pH above two unit of pI (Fig 3A), which suggested a binding of ANS with the amorphous or amyloid aggregates. ANS fluorescence intensities, measured at 480 nm after excitation at 380 nm, showed a negligible effect at pH below two units of their pI (Fig 3B). However, there is a significant difference in the fluorescence intensities between the protein samples above two units of its pI and the sample when incubated with QRMAE under pH below two unit of its pI. As shown in Fig 3 and Table 1; the fluorescence intensity obtained by the controls was very low, but when the protein was incubated with QRMAE above two units of its pI, there was an elevation in the intensities, approximately up to three-folds at 480 nm.

Bottom Line: It was observed that a suitable molar ratio of protein to QRMAE surfactant enthusiastically induces amorphous aggregate formation at a pH above two units of pI.Rosin surfactant QRMAE-albumins interactions revealed a unique interplay between the initial electrostatic and the subsequent hydrophobic interactions that play an important role towards the formation of hydrophobic interactions-driven amorphous aggregate.Amorphous aggregation of proteins is associated with varying diseases, from the formation of protein wine haze to the expansion of the eye lenses in cataract, during the expression and purification of recombinant proteins.

View Article: PubMed Central - PubMed

Affiliation: Protein Biophysics Laboratory, Interdisciplinary Biotechnology Unit, Aligarh Muslim University, Aligarh - 202002, India.

ABSTRACT
Quaternary amine of diethylaminoethyl rosin ester (QRMAE), chemically synthesized biocompatible rosin based cationic surfactant, has various biological applications including its use as a food product additive. In this study, we examined the amorphous aggregation behavior of mammalian serum albumins at pH 7.5, i.e., two units above their isoelectric points (pI ~5.5), and the roles played by positive charge and hydrophobicity of exogenously added rosin surfactant QRMAE. The study was carried out on five mammalian serum albumins, using various spectroscopic methods, dye binding assay, circular dichroism and electron microscopy. The thermodynamics of the binding of mammalian serum albumins to cationic rosin modified surfactant were established using isothermal titration calorimetry (ITC). It was observed that a suitable molar ratio of protein to QRMAE surfactant enthusiastically induces amorphous aggregate formation at a pH above two units of pI. Rosin surfactant QRMAE-albumins interactions revealed a unique interplay between the initial electrostatic and the subsequent hydrophobic interactions that play an important role towards the formation of hydrophobic interactions-driven amorphous aggregate. Amorphous aggregation of proteins is associated with varying diseases, from the formation of protein wine haze to the expansion of the eye lenses in cataract, during the expression and purification of recombinant proteins. This study can be used for the design of novel biomolecules or drugs with the ability to neutralize factor(s) responsible for the aggregate formation, in addition to various other industrial applications.

No MeSH data available.


Related in: MedlinePlus