Pleated sheet, secondary structure of protein

Figure 26.6 (a) The /3-pleated sheet secondary structure of proteins is stabilized by hydrogen bonds between parallel or antiparallel chains, (b) The structure of concanavalin A, a protein with extensive regions of antiparallel / sheets, shown as flat ribbons. 

Just as main-chain NH 0=C hydrogen bonds are important for the stabilization of the a-helix and / -pleated sheet secondary structures of the proteins, the Watson-Crick hydrogen bonds between the bases, which are the side-chains of the nucleic acids, are fundamental to the stabilization of the double helix secondary structure. In the tertiary structure of tRNA and of the much larger ribosomal RNA s, both Watson-Crick and non-Watson-Crick base pairs and base triplets play a role. These are also found in the two-, three-, and four-stranded helices of synthetic polynucleotides (Sect. 20.5, see Part II, Chap. 16). 

The p-pleated sheet secondary structure of a protein, composed of alternating glycine and alanine residues. 

Section 27 19 Two secondary structures of proteins are particularly prominent The pleated sheet is stabilized by hydrogen bonds between N—H and C=0 groups of adjacent chains The a helix is stabilized by hydrogen bonds within a single polypeptide chain... 

Silk is made of fibroin, a fibrous protein with a pleated-sheet secondary structure. 

Secondary Structure of Proteins The secondary structure of a protein is how the polypeptide chain is twisted. There are two common types of secondary structure the alpha helix and the beta pleated sheet. 

Secondary protein structures are the local regular and random conformations assumed by sections of the peptide chains found in the structures of peptides and proteins. The main regular conformations found in the secondary structures of proteins are the a-helix, the fl-pleated sheet and the triple helix (Figure 1.8). These and other random conformations are believed to be mainly due to intramolecular hydrogen bonding between different sections of the peptide chain. 

Be familiar with the various secondary structures of proteins and their dimensions the a helix, /3 turns, pleated sheet structures, and collagen and what dictates the assumption of such... 

Spider web is composed mostly of fibroin, a protein with pleated-sheet secondary structure. The pleated-sheet arrangement allows for multiple hydrogen bonds between molecules, conferring great strength. 

Figure II-2 Major elements of secondary structure of proteins. Left, the a-helix right, representation of the antiparallel pleated sheet structures for polypeptides. (After Pauling, L., and R. B. Corey (1951). Proc Natl Acad Sci USA 37 729).

Figure 5-11. Secondary structure of proteins. Well defined structural elements can be recognised in proteins, such as those illustrated schematically above a helices, parallel or antiparallel f pleated sheets, which can be linked by tight...

In alpha-keratin, shown in Figure 5, the entire length of the protein has an a-helix structure. However, other proteins will have only sections that are a-helixes. Different sections of the same protein may have a pleated sheet secondary structure. These different sections of a protein can fold in different directions. These factors, combined with the inter-molecular forces acting between side chains give each protein a distinct three-dimensional shape. This shape is the tertiary structure of the protein. 

I 28. In comparing the secondary structure of proteins, which description applies to both the a helix and the [)-pleated sheet ... 

Secondary structure (Section 27.19) The conformation with respect to nearest neighbor amino acids in a peptide or protein. The a helix and the P pleated sheet are examples of protein secondary structures. 

Figure 2. The secondary structure of protein. Darker grey portion is the helix and lighter grey portion is the pleated sheet.

The two main types of secondary structural arrangements are the a-helix and the P-pleated sheet. Generally, these conformations generate the secondary structure of proteins. 

The secondary structure of proteins is usually either the regular repetitive pattern of the a-helix or the /3-pleated sheet. The tertiary structure is the three-dimensional structure resulting from the folding of the protein molecule. 

Figure a. Secondary structure of proteins. Left figure shows the a-helix structure. Right figure shows (a) the parallel and (b) the antiparallel /1-pleated sheet structure. 

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