Structure polypeptide folding

The way in which molecular chaperones interact with polypeptides during the folding process is not completely understood. What is clear is that chaperones bind effectively to the exposed hydrophobic regions of partially folded structures. These folding intermediates are less compact than the native folded proteins. They contain large amounts of secondary and even some tertiary... 

Matthews DA, Smith WW, Ferre RA, Condon B, Budahazi G, Sisson W, Villafranca JE, Janson CA, McElroy HE, Gribskov CL et al (1994) Structure of human rhinovirus 3C protease reveals a trypsin-like polypeptide fold, RNA-binding site, and means for cleaving precursor polyprotein. CeU 77 761-771... 

Figure 3 shows the three-dimensional structure of the MoFe protein from Klebsiella pneumoniae, Kpl, obtained at 1.65-A resolution (7). The overall structure of the polypeptides is frilly consistent with that reported earlier for Avl (3). The a and /8 subunits exhibit similar polypeptide folds with three domains of parallel /3 sheet/a helical type. At the interface between the three domains in the a subunit is a wide shallow cleft with the FeMoco at the bottom of the cleft about 10 A from the solvent. FeMoco is enclosed within the a subunit. The P cluster, however, is buried within the protein at the interface between the a and /8 subunits, being bound by cysteine residues from each subunit. A pseudo-twofold rotation axis passes between the two halves of the P cluster and relates the a and (3 subunits. Each af3 pair of subunits contains one FeMoco and one P cluster and thus appears... 

A particular goal of chemical theory is to predict protein structure from the amino acid sequence—to calculate how polypeptides fold into the compact geometries of proteins. One strategy is to develop methods (often based on bioinformatics) for predicting structures approximately and then refining the structures... 

Upon biosynthesis, a polypeptide folds into its native conformation, which is structurally stable and functionally active. The conformation adopted ultimately depends upon the polypeptide s amino acid sequence, explaining why different polypeptide types have different characteristic conformations. We have previously noted that stretches of secondary structure are stabilized by short-range interactions between adjacent amino acid residues. Tertiary structure, on the other hand, is stabilized by interactions between amino acid residues that may be far apart from each other in terms of amino acid sequence, but which are brought into close proximity by protein folding. The major stabilizing forces of a polypeptide s overall conformation are ... 

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. 

Keywords Design, Polypeptide, Catalysis, Metalloprotein, Heme, Structure, Protein folding, Glycopeptide. 

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). 

NiFe hydrogenase, see NiFe hydrogenase nitrate reductase, 47 3, 5,13-14, 396,403-406, 472, 475 NMR studies, 4na5 -Tll electron relaxation times, 47 252-257 polypeptide folding, 47 271-276 reduction potential, 47 265-266 solution structure, 47 266-271 valence delocalization, XJOSl, 259, 261-265... 

Was this your answer Hemoglobin s primary structure is its sequence of amino adds along each polypeptide.The twisting of each polypeptide into an alpha helix is its secondary structure. The folding up of the full length of each alpha helix into a globular shape is its tertiary structure.The combination of the four polypeptides is the quaternary structure. 

Seibert, M.M., Patriksson, A., Hess, B., and van der Spoel, D. (2005) Reproducible polypeptide folding and structure prediction using molecular dynamics simulations. /. Mol. Biol. 354,173. 

The overall polypeptide fold of the a subunit is that of an 8-fold a//8 barrel (Fig. 7.2 and color plate ).7) Similar structures have been observed in more than 18 other... 

Answer Myoglobin is all three. The folded structure, the globin fold, is a motif found in all globins. The polypeptide folds into a single domain, which for this protein represents the entire three-dimensional structure. 

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