Medium-range interactions peptides

Hydrophobic periodicity can have such a large influence on the formation of secondary structure that it dominates over short- and medium-range interactions (DeGrado and Lear, 1985). This has been demonstrated recently, using a set of designed peptides with leucyl and lysyl residues in identical ratios but with different hydrophobic periodicities. 

Some of the different theoretical approaches, prediction methods, and simulation of protein folding are briefly introduced here. The methods for evaluating, first the conformational preferences of a single peptide unit, and second the conformational preferences of a polypeptide chain, are discussed. Models that use short- and medium-range interactions are briefly analyzed. The results of these different predictive methods of secondary structures are compared. Actually the refinements of these predictive methods are under study in the main laboratories of this field of study. It is evidently of great... 

Tertiary structure of proteins is considered to be the result of a complex interplay of short-range, medium-range and long-range interactions along the peptide chain. In a first approximation, the secondary structure is thought to be mainly influenced by short-range interactions. The evaluation of the relationship b een primary and secondary structure therefore appears to be the first step on the way to unravel the interdependent parameters responsible for tertiary structure formation. 

Superose gel material of Pharmacia Biotech is a highly epichloro-hydrine cross-linked agarose matrix that has a pH range of 3-12 (short term 1-14). Hydrophilic interactions may be noticeable for lipids, peptides, and small aromatic compounds, but such interactions might even improve resolution. Superose medium is available in two different porosities Superose 6 HR 10/ 30 (bead size 13 2 /um maximum pressure 1.5 MPa) and Superose 12 HR 10/30 (bead size 10 2 /um maximum pressure 3.0 MPa). 

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