Biomacromolecules in Solution

The driving force of the reaction, which is the free-energy change, AG can be written as 

At equilibrium AG = 0, the standard free energy change, AG is related to the equilibrium constant, K according to 

The equilibrium constaut cau now be related to the other thermodynamic states, the standard enthalpy change (AH ) and the standard entropy change (AS ) by 

Biomacromolecules, by C. Stan Tsai Copyright 2007 John Wiley Sons, Inc. 

Thus the thermodynamic variables, AG°, AH° and AS° for a reaction can be obtained by measuring equilibrium concentrations at different temperatures. 

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Applications similar to but more powerful than ORD especially for functional groups such as C=0. Conformational analysis of biomacromolecules in solutions. 

Circular dichroism Difference in intensity of absorption of right- and left-circularly polarized light by functional groups in asymmetric environment N, P, G Applications similar to but more powerful than ORD especially for functional groups such as 0=0. Conformational analysis of biomacromolecules in solutions. 

Solvation of polar moieties in water is also important for understanding structure of biomacromolecules in solution. Given the small enthalpic difference between the folded and unfolded states, the... 

We note that the just described pulse sequence is identical to the 2D exchange NMR experiment of solution NMR, which is an isotropic-shift exchange experiment. The same sequence is also used in 2D nuclear Overhauser effect spectroscopy (NOESY) NMR in solution and used extensively in the elucidation of the stmcture of biomacromolecules in solution. There, however, the exchange is based on incoherent magnetization transfer by incoherent cross-relaxation. ... 

The swollen specific volume n p (cm /g) is defined when an anhydrous biomacromolecules essentially expand in suspended or dissolved in solution because of solvent association, and... 

Are biomacromolecules of greater mass than that of rubredoxin (6 kDa), in particular enzymes (typically, >50 kDa), capable of such rapid conformational adjustment with decreasing temperature At present the answer appears to be We do not know. Unfortunately, the reduction potentials) of enzymes in solution is not usually determinable with direct electrochemistry, so you are invited to find and explore other molecular properties to probe as a function of temperature, for example, (de) protonations near paramagnetic sites that can be followed both by optical and by EPR spectroscopy. 

The two-stage procedure eliminates the detrimental effect of acid, but an alcohol, which is produced in the course of precursor hydrolysis Equation (2), remains in solution. This can cause unfolding of the biomacromolecule and denaturation of... 

The silica nucleated only on the biomacromolecules. By decreasing the THEOS amount in solution from 3 to 0.03 wt.%, we observed a curtailment of the particle diameter to the macromolecular dimension. This constitutes evidence that most of the silica generated in situ was used to form a shell. 

Yang, Y. H., Shao, Z. Z., Chen, X., and Zhou, P. (2004). Optical spectroscopy to investigate the structure of regenerated Bombyx mori silk fibroin in solution. Biomacromolecules 5, 773-779. 

The water-in-oil-in-water (w/o/w) emulsion method (Figure 11.4) is the predominant method used for encapsulation of biomacromolecules in these microparticles. Protein solution forms the internal water phase of the w/o/w emulsion. Loading efficiency of the microparticles has not been optimal using water or buffer as an internal phase, so water is sometimes substituted with polymeric liquids, such as low molecular weight polyethylene glycol. The primary emulsion is then added to a secondary liquid phase, forming the secondary emulsion. The solvent for the... 

To improve and control cell-fiber interactions, the fiber meshes can be either composed of biomacromolecules or postfunctionalized with appropriate biomolecules. The question arises as to which materials can be electrospun. In principle, all polymers can be spun if they provide enough entanglements in solution and adequate interactions between the solvent and solute. Biopolymers, in particular, show dominant H-bonding and/or polyelectrolyte effects, which lead to a strong viscosity increase or poor solvent evaporation. In order to prevent such... 

The structure determination of organic molecules in solution — constitution, configuration and conformation — is probably the most important application of high-resolution NMR spectroscopy. Sophisticated methods based on classical NMR parameters like chemical shifts, /-couplings and nuclear Overhauser enhancement (NOE) have been developed for deriving structural models.1 2 The approach has been successfully applied to a vast number of molecules including thousands of biomacromolecules and uncountable natural and synthetic products. 

In solution, the flexibility of the polymer chain allows the polymer to collapse into a compact, randomly coiled structure rather than to retain an extended form. A transition between these two forms can be observed depending on solvent quality and temperature and is best known as the rod-to-coil transition of biomacromolecules such as DNA. 

Nuclear Magnetic Resonance (NMR) spectroscopy is a powerful method to determine the structure of biomacromolecules and their complexes in solution. It allows determination of the dynamics of proteins, RNA, DNA, and their complexes at atomic resolution. Therefore, NMR spectroscopy can monitor the often transient weak interactions in the interactome of proteins and the interaction between proteins and small-molecule ligands. In addition, intrinsically unstructured proteins can be investigated, and first reports of structure determination of membrane proteins in the immobilized state (solid state) are developing. This review will introduce the fundamental NMR observables as well as the methods to investigate structure and dynamics, and it will discuss several examples where NMR spectroscopy has provided valuable information in the context of Chemical Biology. 

Thermal anomalies in water near surfaces as diverse as diamond, glass, quartz, clays, mica, fatty acids, chondroitin 4-sulfate, polystyrene, polyvinyl acetate, cellulose, gelatin, and other biomacromolecules (such as enzymes and other proteins) in solution are known to occur close to the critical temperatures. Tj has also been shown to be unaffected by the concentration of electrolytes in solution. The concentrations of alkali chlorides (Li% Na", K, Rb and Cs" ) were varied by a factor of ICf with no detectable systematic effects on Tj (Drost-Hansen, 1985). However, the evidence for the paradoxical effect does not rely solely on the substrate independence of Tjj. 

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