Amino-acid residues glycine

Bile salts are structurally similar to soap in that they contain a polar head group (e.g., the charged amino acid residue glycine) and a hydrophobic tail (the steroid ring system). 

Fig. C5.9 One of the two most common secondary structures of protein /3-sheet. It is stabilized by hydrogen bonds between atoms of the main polypeptide chain, not involving the aminoacid residues side groups, which extend above and below the sheet. As in case of a-helix, only the least bulky amino acid residues, glycine and alanine, are used for this...

The importance of aperiodicity on the electronic structure of proteins can be demonstrated by taking a polypeptide chain composed of three different amino-acid residues glycine, alanine, and serine (see Figure 4.1). 

However, all these results were obtained by analysis of unfractionated clupeine. The complete amino-acid sequences recently determined for the three components of clupeine from Pacific herring (Clupea pallasii) (Ando et al,y 1962 Ando and Suzuki, 1966, 1967) confirmed the presence of an amino-acid residue, glycine, as a constituent and of the N-terminal alanine in addition to the N-terminal proline in some of the clupeine molecules. At that time no complete fractionation of clupeine from Clupea harengus into a number of homogeneous components had been accomplished. 

Biosynthesis. Two closely related genes encode the three mammalian tachykinins. The preprotachykinin A gene encodes both substance P and substance K, while the preprotachykinin B gene encodes neuromedin K (45—47). The active sequences are flanked by the usual double-basic amino acid residues, and the carboxy-terrninal amino acid is a glycine residue which is decarboxylated to an amide. As with most neuropeptide precursors, intermediates in peptide processing can be detected, but their biological activities are not clear (ca 1994). 

Observed values for all residue types except glycine. Each point represents (j) and values for an amino acid residue in a well-refined x-ray structure to high resolution, (c) Observed values for glycine. Notice that the values include combinations of (j) and that are not allowed for other amino acids. (From J. Richardson, Adv. Prot. Chem. 34 174-175, 1981.1... 

Collagen Collagen is an extracellular structural protein 1052 amino acid residues. Collagen has an minsnal amino acid composidon it is about one-third glycine and is rich in proline. Note diat it also lacks Cys and Trp and is deficient in aromadc amino acid residues in general. 

Xmino-benzol, n. aminobenzene, aniline, -essig-siure,/. aminoacetic acid, glycine, -kohlen-saure, /. amidocarbonic acid, carbamic acid, sfiure, /. amino acid, -saurerest, m. amino acid residue, -verbindung, /. amino compound. -zucker, m. amino sugar. 

It is a peptide containing 27 amino acid residues containing the amino acids L-histidine (His) L-aspartic acid (Asp) L-serine (Ser) glycine (Gly) L-threonine (Thr) L-phenyl-alanine (Phe) L-glutamic acid (Glu) L-glutamine [Glu(NHj)] L-leucine (Leu) L-arginine (Arg) L-alanine (Ala) and L-valinamide (Va -NHj). 

Proteins are large biomolecules made up of a-amino acid residues linked together by amide, or peptide, bonds. Chains with fewer than 50 amino acids are often called peptides, while the term protein is reserved for larger chains. Twenty amino acids are commonly found in proteins all are a-amino acids, and all except glycine have stereochemistry similar to that of l sugars. In neutral solution, amino acids exist as dipolar zwitterions. 

Glycine receptor function is modulated by alcohols and anesthetics [4]. Amino acid residue al(S267) is critical for alcohol potentiation, as mutation to small residues (Gly, Ala) enhance, and mutation to large residues (His, Cys, Tyr) diminish the ethanol effect. Glycine recqrtor modulation by Zn2+ involves structural determinants located within the large N-terminal domain. Additional glycinergic modulators include neuroactive steroids and the anthelmintic, ivermectin, which activates glycine receptors by a novel, strychnine-insensitive mechanism. 

The intramembrane segments consist of 21-25 amino acid residues with overrepresentation of the hydrophobic residues Phe, He, Leu, Val, Trp, Tyr, but also of Pro and Cys. This may suggest that S-S bridge formation is part of stabilizing intramembrane structures. Prolines or glycines break the continuity of membrane... 

Fig. 7.6 The 33-residue fragment of the winter flounder antifreeze protein (AFP), constructed by the conjoining of the Aa amino acid residues defined within the glycine mold , pictured in terms of its 0.001 au isodensity envelope, its van der Waals envelope. This is a view showing the ice-binding motif. It is believed that the AFP strand binds... 

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