Polypeptides folding

Structural Formula Has folded polypeptide chain of 212 residues with a molecular weight of about 23/too. 

Baars MWPL, Meijer EW (2000) Host-Guest Chemistry of Dendritic Molecules. 210 131-182 Balczewski P, see Mikoloajczyk M (2003) 223 161-214 Ballauff M (2001) Structure of Dendrimers in Dilute Solution. 212 177-194 Baltzer L (1999) Functionalization and Properties of Designed Folded Polypeptides. 202 39-76 Balzani V, Ceroni P, Maestri M, Saudan C, Vicinelli V (2003) Luminescent Dendrimers. Recent Advances. 228 159-191 Barre L, see Lasne M-C (2002) 222 201-258 Bartlett RJ, see Sun J-Q (1999) 203 121-145... 

Baltzer L (1999) Functionalization and Properties of Designed Folded Polypeptides. 202 ... 

Balczewski P, see Mikoloajczyk M (2003) 223 161-214 Ballauff M (2001) Structure of Dendrimers in Dilute Solution. 212 177-194 Baltzer L (1999) Functionalization and Properties of Designed Folded Polypeptides. 202 39-76... 

Frequently, metal ions are associated with the prosthetic group or cofactor. Heme rings usually contain a chelated iron atom. Occasionally, however, these metals are merely bound within folded polypeptide regions with no additional organic constituents required. Many metal ions are known to participate in enzymatic activity. One or more of the ions of Na, K, Ca, Zn, Cu, Mg, Mn, as well as Co and Mo are often required by enzymes to maintain activity. 

Proteins are highly complex, folded polypeptide chains consisting of at least 20 different amino acids that are strung together in unique sequences, which relate to structure and function. Particular amino acids in proteins may be further modified post-translationally to contain a wide variety of covalent modifications normally found in native proteins. The way in which a peptide chain is wrapped and folded governs each amino acid s relative exposure to the outside environment, but post-translational modifications also can obscure the protein surface from easy access to the solvent environment. 

However, just considering the individual properties of each amino acid type is not enough to determine its accessibility to the surrounding aqueous environment. There have been many attempts at developing analytical models with predictive value for determining buried or surface accessible amino acids in a folded polypeptide chain. These studies have concluded fractional assignments for each residue that relate to its accessible surface area (ASA) or its solvent exposed area (SEA). 

Speed, M. A., Wang, D. I. C., and King, J. (1996). Specific aggregation of partially folded polypeptide chains The molecular basis of inclusion body composition. Nat. Biotechnol. 14, 1283-1287. 

The nature of the amino acid residues is of prime importance in the development and maintenance of protein structure. Polypeptide chains composed of simple aliphatic amino acids tend to form helices more readily than do those involving many different amino acids. Sections of a polypeptide chain which are mainly non-polar and hydrophobic tend to be buried in the interior of the molecule away from the interface with water, whereas the polar amino acid residues usually lie on the exterior of a globular protein. The folded polypeptide chain is further stabilized by the presence of disulphide bonds, which are produced by the oxidation of two cysteine residues. Such covalent bonds are extremely important in maintaining protein structure, both internally in the globular proteins and externally in the bonding between adjacent chains in the fibrous proteins. 

A research area in which obvious applications are to be found include the design of new catalysts and a number of examples have nowbeen reported of the catalysis of chemical reactions by designed folded polypeptides [11 -13]. So far, enzyme-like selectivities and efficiencies have not been achieved but, eventual-... 

This review describes designed and folded helical proteins, )5-sheet proteins, a )5)5a-motif and TASP proteins that are targets for functionalization. The functionalization of folded polypeptides using natural amino acids to form catalysts... 

In the amino acid sequence of a folded polypeptide is encoded its three-dimensional structure, its folding pathway and the spatial organization of the residues that are responsible for its function (Fig. 1). 

Fig. 2. Schematic representations of the common buUding blocks of folded polypeptides, the a-helrx and the /i-sheet. Typical distances between a-carbons in the folded secondary strnc-tures are shown and define the dimensions that can be used for the construction of reactive sites in single motifs. The distances between a-carbons of helices depend on the type of helix, and those of 8-sheets are very different on the concave and on the convex sides and can easily vary by an Angstrom or more...

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