In 1989, Manning, Patel, and Borchardt wrote a review of protein stability (Manning et al, Pharm Res 6:903-918, 1989), which has been widely referenced ever since At the time, recombinant protein therapy was still in its infancy This review summarizes the advances that have been made since then regarding protein stabilization and formulation In addition to a discussion of the current understanding of chemical and physical instability, sections are included on stabilization in aqueous solution and the dried state, the use of chemical modification and mutagenesis to improve stability, and the interrelationship between chemical and physical instability

Stability of Protein Pharmaceuticals: An Update

The Foundations of Statistics By Prof. Leonard J. Savage. (Wiley Publications in Statistics.) Pp. xv + 294. (New York; John Wiley and Sons, Inc.; London: Chapman and Hall, Ltd., 1954.) 48s. net.

Probability and Statistical Inference

Water is an essential participant in the stability, structure, dynamics, and function of proteins and other biomolecules. Thermodynamically, changes in the aqueous environment affect the stability of biomolecules. Structurally, water participates chemically in the catalytic function of proteins and nucleic acids and physically in the collapse of the protein chain during folding through hydrophobic collapse and mediates binding through the hydrogen bond in complex formation. Water is a partner that slaves the dynamics of proteins, and water interaction with proteins affect their dynamics. Here we provide a review of the experimental and computational advances over the past decade in understanding the role of water in the dynamics, structure, and function of proteins. We focus on the combination of X-ray and neutron crystallography, NMR, terahertz spectroscopy, mass spectroscopy, thermodynamics, and computer simulations to reveal how water assist proteins in their function. The recent advances in computer s...

Water Determines the Structure and Dynamics of Proteins

At low temperatures, proteins exist in a glassy state, a state that has no conformational flexibility and shows no biological functions. In a hydrated protein, at temperatures ≳220 K, this flexibility is restored, and the protein is able to sample more conformational substates, thus becoming biologically functional. This “dynamical” transition of protein is believed to be triggered by its strong coupling with the hydration water, which also shows a similar dynamic transition. Here we demonstrate experimentally that this sudden switch in dynamic behavior of the hydration water on lysozyme occurs precisely at 220 K and can be described as a fragile-to-strong dynamic crossover. At the fragile-to-strong dynamic crossover, the structure of hydration water makes a transition from predominantly high-density (more fluid state) to low-density (less fluid state) forms derived from the existence of the second critical point at an elevated pressure.

https://www.pnas.org/content/pnas/103/24/9012.full.pdf

Observation of fragile-to-strong dynamic crossover in protein hydration water.

In this Letter we propose the use of hypersonic phononic crystals to control the emission and propagation of high frequency phonons. We report the fabrication of high quality, single crystalline hypersonic crystals using interference lithography and show that direct measurement of their phononic band structure is possible with Brillouin light scattering. Numerical calculations are employed to explain the nature of the observed propagation modes. This work lays the foundation for experimental studies of hypersonic crystals and, more generally, phonon-dependent processes in nanostructures.

/pdf/hypersonic-phononic-crystals-p7jphcieat.pdf

Hypersonic phononic crystals.

Two onsets of anharmonicity are observed in the dynamics of the protein lysozyme. One at T approximately 100 K appears in all samples regardless of hydration level and is consistent with methyl group rotation. The second, the well-known dynamical transition at T approximately 200-230 K, is only observed at a hydration level h greater than approximately 0.2 and is ascribed to the activation of an additional relaxation process. Its variation with hydration correlates well with variations of catalytic activity suggesting that the relaxation process is directly related to the activation of modes required for protein function.

Onsets of Anharmonicity in Protein Dynamics

Influence of hydration on the dynamics of lysozyme.

http://absimage.aps.org/image/MAR05/MWS_MAR05-2004-000596.pdf

Despite extensive efforts in experimental and computational studies, the microscopic understanding of dynamics of biological macromolecules remains a great challenge It is known that hydrated proteins, DNA and RNA, exhibit a so-called "dynamic transition" It appears as a sharp rise of their mean-squared atomic displacements r2 at temperatures above 200-230 K Even after a long history of studies, this sudden activation of biomolecular dynamics remains a puzzle and many contradicting models have been proposed By combining neutron and dielectric spectroscopy data, we were able to follow protein dynamics over an extremely broad frequency range Our results show that there is no sudden change in the dynamics of the protein at temperatures around approximately 200-230 K The protein's relaxation time exhibits a smooth temperature variation over the temperature range of 180-300 K Thus the experimentally observed sharp rise in r2 is just a result of the protein's structural relaxation reaching the limit of the experimental frequency window The microscopic mechanism of the protein's structural relaxation remains unclear

The origin of the dynamic transition in proteins

Analysis of Raman and neutron scattering spectra of lysozyme demonstrates that the protein dynamics follow the dynamics of the solvents glycerol and trehalose over the entire temperature range measured 100-350 K. The protein's fast conformational fluctuations and low-frequency vibrations and their temperature variations are very sensitive to behavior of the solvents. Our results give insight into previous counterintuitive observations that protein relaxation is stronger in solid trehalose than in liquid glycerol. They also provide insight into the effectiveness of glycerol as a biological cryopreservant.

/pdf/protein-and-solvent-dynamics-how-strongly-are-they-coupled-48gzk53tla.pdf

Joon Ho Roh

Papers

Onsets of Anharmonicity in Protein Dynamics

Influence of hydration on the dynamics of lysozyme.

Onsets of Anharmonicity in Protein Dynamics

The origin of the dynamic transition in proteins

Protein and solvent dynamics: how strongly are they coupled?