Proteins, self-assembly primary protein structure

The self-assembling character of bilayer membranes is demonstrated by the formation of free-standing cast films from aqueous dispersions of synthetic bilayer membranes. The tendencies for association are sufficiently strong to allow the addition of guest molecules (nanoparticles, proteins, and various small molecules) to these films where the connective forces are secondary in nature and not primary. Synthetic polymer chemists have made use of these self-assembling tendencies to synthesize monolayer films. In particular, a monomer that contains both reactive groups and hydrophobic and hydrophilic areas is cast onto an appropriate template that self-assembles the monomer, holding it for subsequent polymerization. Thus, a bilayer structure is formed by... 

Not only proteins and their oligomers, but nucleic acids as well give beautiful examples of self-organization - think of the formation of the DNA duplex, where the primary structure of the two strands determines the rules for self-assembly or the folding of t-RNA. 

At first glance, the notion that the assistance of a molecular chaperone may be required for the folding and/or assembly of other proteins appears to be at variance with the work of Anfinsen (5), who demonstrated that bovine pancreatic ribonuclease can be denatured and consequently renatured in vitro, in the absence of other cofactors. This experiment has been repeated since with many other proteins, including Rubisco (4) thus, it has been assumed that the primary sequence is able and sufficient to direct the correct self-folding of all proteins into their functional tertiary structure. 

One of the most remarkable properties of self-assembly is its ability to generate exceedingly coinplica ted supramolecular structures from fairly simple components. Perhaps the most elegant embodiment of this phenomenon is protein stmcture. Proteins exhibit at least four hierarchies of stmcture primary, secondary, tertiary, and quaternary stmctures. Primary stmcture describes the covalent connections making up the sequence of amino acids in each strand. Secondary stmcture involves local architectural elements created when portions of a strand... 

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