Obtaining protein solvent accessible surface area when structural data is unavailable using osmotic pressure

Abstract

Here, we provide an algorithm that predicts solvent accessible surface area (SASA) using concentrated solution osmotic pressure data. Sheep hemoglobin monomer and β‐lactoglobulin are used for verification. Additionally, SASA for structurally unknown calf lens α‐crystallin aggregate is predicted. Using osmotic pressure data, the predicted SASA value for sheep hemoglobin, 22,398 ± 1,244 Å2, was in excellent agreement with computational model predictions (24,304 Å2‐26,100 Å2). Similarly, predicted SASA values for bovine β‐lactoglobulin in pH solutions of pH 5.1, 6.0, and 8.0, were 5,765 ± 1,031 Å2, 6,656 ± 1,082 Å2, and 9,141 ± 1,060 Å2, respectively, were in good agreement with the computationally determined SASA value (7,500 Å2–8,628 Å2). Predicted SASA for the aggregate of calf lens α‐crystallin (800 kDa) was found to be 417,691 ± 16,790 Å2. These results illustrate that this novel method can provide an important experimental alternative in estimating SASA for proteins and, possibly, their complexes in solution. © 2011 American Institute of Chemical Engineers AIChE J, 2012

Interactions in protein mixtures. Part I: Second virial coefficients from osmometry

“…This was addressed by Simonet, Garnier, and Doublier (2002) in their study of a guar gum/dextran mixture using static light scattering, a frequently used technique for measuring virial coefficients (Bonnet e et al, 1999;Ducruix et al, 1996;Guo et al, 1999;Malo de Molina, Appavou, & Gradzielski, 2014;Muschol & Rosenberger, 1995;Rosenbaum, D., Zamora & Zukoski, 1996;Rosenbaum, D. F., Kulkarni, Ramakrishnan & Zukoski, 1999;Velev, Kaler, & Lenhoff, 1998;Wilson, 2003). Virial coefficients can also be determined using various chromatography methods (Ahamed et al, 2005;Bloustine, 2005;Le Brun et al, 2009) or membrane osmometry (Ahamed et al, 2005;Mc Bride & Rodgers, 2012;McCarty & Adams Jr, 1987;Schaink & Smit, 2000, 2007Yousef, Datta, & Rodgers, 1998).…”

Predicting the Activity Coefficients of Free-Solvent for Concentrated Globular Protein Solutions Using Independently Determined Physical Parameters

“…The parameters of the free-solvent model have been shown to be remarkably robust and well-within independently determined values when regressed relative to measured osmotic pressure for highly concentrated protein solutions [5]–[9], [11]. As an example, the regressed hydration number, , for all globular proteins measured was found to be well within the 17 O NMR approximation of 1 g H 2 O/g globular protein [12] but more precisely determines the value to be a monolayer of water with 0.6% when compared to the solvent accessible surface area (SASA) of each protein.…”

Interactions in protein mixtures. Part II: A virial approach to predict phase behavior

“…Experimentally, the second virial coefficient can be obtained using different scattering techniques (Bonnet e et al, 1999;Ducruix, Guilloteau, Ri es-Kautta, & Tardieu, 1996;Guo et al, 1999;Malo de Molina, Appavou, & Gradzielski, 2014;Muschol & Rosenberger, 1995;Rosenbaum, Kulkarni, Ramakrishnan, & Zukoski, 1999;Rosenbaum, Zamora, & Zukoski, 1996;Velev, Kaler, & Lenhoff, 1998;Wilson, 2003), sedimentation experiments (Edmond & Ogston, 1968) or membrane osmometry (Ahamed, Ottens, van Dedem, & van der Wielen, 2005;Mc Bride & Rodgers, 2012;McCarty & Adams, 1987;Schaink & Smit, 2000, 2007Yousef, Datta, & Rodgers, 1998). We have decided to use membrane osmometry because of its direct measurement of the osmotic pressure, and because the measured values are number-averaged and therefore insensitive to sample impurities, like dust.…”