Glycine codons

Selective formation of microparticles from polynucleotides and lysine-rich proteinoids rich in individual radioactive amino acid has been studied and the focus of attention is on those homoanticodonic amino acids having one homogeneous codon (glycine, CCC lysine, UUU proline, GGG and phenylalanine, AAA)58). Precipitation of individual amino acid rich proteinoids with each of homopolyribonucleotides, with and without Mg2+, was tested58>. The results show that three (Lys-rich, Gly-rich,... 

Because of the considerations just made, it is of interest to divide amino acids (see Fig. 10.3) into three classes (i) those that only contain G and/or C in the first and second positions of their codons (ii) those that only contain A and/or T and (iii) those that contain G and/or C as well as A and/or T. The GC class comprises four amino acids, alanine, arginine (quartet codons), glycine, and proline the AT class comprises seven amino acids, asparagine, isoleucine, leucine (duet codons), lysine, methionine, phenylala-... 

X can be any of the four nucleobases—G, A, C or U thus, four anticodons can be formed GGC, GAC, GCC and GUC. The antiparallel structure contains the codons GCC, GUC, GGC and GAC. Today, these codons code for the four amino acids alanine, glycine, valine and aspartic acid. These are, astonishingly, the four protein building blocks produced in the best yields in the Miller-Urey experiment, and they... 

Frameshift suppression is also possible. This can be achieved by a second mutation in a tRNA gene such that the anticodon of a tRNA molecule consists of 4 bases rather than 3, for example, an extra C residue in the CCC anticodon sequence of a glycine tRNA gene. This change will allow correction of a +1 frameshift involving the GGG codon for glycine (Bossi, 1985). 

The many (possibly more than 30) types of collagens found in human connective tissues have substantially the same chemical structure consisting mainly of glycine with smaller amounts of proline and some lysine and alanine. In addition, there are two unusual amino acids, hydroxyproline and hydroxylysine, neither of which has a corresponding base-triplet or codon within the genetic code. There is therefore, extensive post-translational modification of the protein by hydroxylation and also by glycosylation reactions. 

Ribosomal synthesis of peptides proceeds through translation of messenger ribonucleic acid (mRNA) and utilizes the 20 primary L-a-amino acids. These amino acids are incorporated with the use of specific transfer ribonucleic acid (tRNA) codons. The 20 primary a-amino acids, with the exception of glycine that is achiral, are characterized by an L-configuration at the a-position (Figure 1). In general, most proteins are found to be composed of these 20 L-a-amino acids, as such they are referred to as protein amino acids. 

Kreimer S, Andreesen JR. 1995. Glycine reductase of Clostridium litorale. Cloning, sequencing, and molecular analysis of the grdAB operon that contains two in-frame TGA codons for selenium incorporation. Eur J Biochem 234 192-9. 

Predicting Anticodons from Codons Most amino acids have more than one codon and attach to more than one tRNA, each with a different anticodon. Write all possible anticodons for the four codons of glycine (5 )GGU, GGC, GGA, and GGG. 

Cp4 and the secreted segment to the 5 border of the first membrane exon the donor splice site lies within a GGU glycine codon that is retained in ps mRNA. Which form of mRNA is produced depends on competition between splicing and polyadenylation at the p.s and pm poly(A) sites (Peterson and Perry, 1986 Tsurushita et al., 1987 Galli et al., 1988 Peterson and Perry, 1989). The balance between the two mRNA products determines the proportion of membrane and secreted IgM. Activation of the B lymphocyte appears to tip the balance in favor of secretion, but the regulatory signals are not known. 

The element Se—not really a metal—is known to play a key role in enzymes such as the well-known glutathione peroxidase, formate dehydrogenase, glycine reductase, and the previously mentioned hydrogenases (Chapter 9). The unusual amino acid selenocysteine has a unique codon on the DNA (TGA/UGA), but selenation of serine also appears to be possible [16]. A brief review on Selenium can be found in the literature [17],... 

RNA binding loop postulated in Figure 6.1 may have been specific only for L-con-figuration of the N-Ca-Ccarbonyl group, which is uniform in all protein amino acids (except glycine), whereas the RNA tail controlled the side-chain fit and thus the codon-specific interactions. 

This nine-base strand of m-RNA contains three codons UUC GGC, and, AUU, and calls for the amino acids phenylalanine, glycine, and, isoleucine in that order.7 Thus the order of the bases in DNA dictates a particular sequence in the m-RNA strand. When the m-RNA strand is complete, it leaves the nucleus and heads for the ribosomes in the cytoplasm. 

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