Solvent-protein interactions functional roles

Extensive structure function studies have identified Phe , which is centrally disposed on the gplSO CHR interface as critical for ligand engagement for all human gp 130-cytokines (Fig. 5) (Bravo et al, 1998 Horsten et al, 1997 Kurth et al, 1999 Li and Nicholas, 2002). The use of a bulky hydrophobic solvent exposed residue at site 11 is also observed in the GH/GHR complex (de Vos et al, 1992) and the EPO/EPOR complex (Syed et al, 1998) suggesting a more fundamental role in mediating protein-protein interactions. In these cases, a bulky tyrosine docks into a hydrophobic pocket on the cytokine formed by the Ca backbone of helix C. 

Noncovalent interactions play a key role in biodisciplines. A celebrated example is the secondary structure of proteins. The 20 natural amino acids are each characterized by different structures with more or less acidic or basic, hydrophilic or hydrophobic functionalities and thus capable of different intermolecular interactions. Due to the formation of hydrogen bonds between nearby C=0 and N-H groups, protein polypeptide backbones can be twisted into a-helixes, even in the gas phase in the absence of any solvent." A protein function is determined more directly by its three-dimensional structure and dynamics than by its sequence of amino acids. Three-dimensional structures are strongly influenced by weak non-covalent interactions between side functionalities, but the central importance of these weak interactions is by no means limited to structural effects. Life relies on biological specificity, which arises from the fact that individual biomolecules communicate through non-covalent interactions." " Molecular and chiral recognition rely on... 

Water has an essential role in living systems and is ultimately involved in the structure and function of biological polymers such as proteins. However, in this contribution we sh tll focus primarily not on what the water does for the blopolymer but rather on the effects that the biopolymer has on the water that Interacts with it. Of Interest are alterations in the structural, energetic, and dynamic properties of the water molecules. Studies of the rotational mobility of water molecules at protein surfaces have been interpreted by dividing the solvent molecules into three groups U). The most rapidly reorienting group has a characteristic rotational reorientation time (t ) of not more than about... 

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