Adenosine amino acid sequence

There are two classes of synthetase, each with 10 members. The amino acid sequences of these two classes have regions which are identical for all enzymes of the particular class (Eriani, 1990). The class 1 synthetases acylate the tRNA at the 2 -hydroxyl of the terminal adenosine, while the class 2 enzymes acylate predominantly at the 3 -function of the ribose. 

Among the strong preferences that have been observed, it seems that Arg prefers binding to guanosine, Asp to adenosine and cytosine and Leu to thymidine. However, we are not yet sufficiently advanced to define a set of coding rules (i.e. to define the amino acid sequence of one or more zinc fingers, which would bind to a specific DNA sequence). 

Potassium ion channels are a veiy diverse family of membrane proteins, with numerous sub-types both in the CNS and peripheral tissues, in particular in the heart. On the basis of the amino acid sequence of the pore-forming a sub-unit, they are classified into two main super-families, the inward rectifier superfamily (which includes receptor-coupled, adenosine 5 -triphosphate (ATP)-sensitive and voltage-dependent channels) and the Sha/cer-related superfamily (which includes Ca2-H-dependent channels). 

The Ga proteins can be classified on the basis of similarities in their amino acid sequences and coupling to effector proteins. The four major categories are Gas, Gai, Gaq, and Gall and these are responsible for activating different signaling pathways in cells. Gas and Gai stimulate and inhibit adenylate cyclase, respectively. Adenylate cyclase is an enzyme that catalyzes the formation of cyclic adenosine monophosphate (cAMP), an intracellular second messenger... 

Opening of a base pair in tRNAGln accompanies complexation with its cognate glutaminyl-tRNA synthetase [715]. All the tRNAs have an L-shaped three-dimensional structure as shown in Fig. 20.8. At one end of the L is the anticodon triplet it codes for the amino acid for which the respective tRNA is specific. At the other end of the L is the amino acid acceptor stem with the free O H of the terminal invariant adenosine, A76 in tRNAoln. The amino acid is attached here through an ester linkage in a reaction which is catalyzed by enzymes called synthetases. In contrast to the uniform tRNA structure, synthetases vary in amino acid sequence, molecular weight and subunit composition. 

The application of LSR to amino-acids has received some attention. (451-456, 498) Such studies are an essential preliminary to the use of LSR for amino-acid sequence determination in simple peptides and proteins. The latter are discussed more comprehensively in Section G. A detailed study has been made (453) of the interaction of Eu(iii), Pr(iii), Gd(iii), and La(iii) with iV-acetyl-L-3-nitrotyrosine in order to characterize the nitrotyrosine residue as a potential specific lanthanide binding site in proteins. The parameters of the dipolar interaction indicate a significant contribution from non axially symmetric terms. The conformations of the nucleotides cyclic j8-adenosine 3, 5 -phosphate (3, 5 -AMP) (457, 458) and adenosine triphosphate (ATP) (459) have been deduced using LSR. In the former case the conformation of the ribose and phosphate groups is consistent with the solid state structure. A combination of lanthanide shift and relaxation reagents was used to deduce the most favoured family of conformations for ATP in aqueous solution. One of these conformations corresponds closely to one of the crystal structure forms. 

There is another large class of receptors whose occupancy by an agonisf leads to inhibition of adenylate cyclase. These include the tt2 adrenergic receptors, receptors for acetylcholine, adenosine, prostaglandin E2 (Chapter 21), somatostatin, and some receptors for dopamine. Their responses are mediafed by inhibitory proteins Gj, which closely resemble Gg in their sizes, amino acid sequences, and heterotrimeric structures, but which inhibit adenylate cyclase when activated. A clear distinction between the Gg and Gj proteins is evident in the fact that Gg is irreversibly activated by the action of cholera toxin, while G loses its ability to respond to occupied receptors when modified by the action of Pertussis toxin (Box 11-A). A specialized heterotrimeric G protein known as transducin mediates the light-induced activation of a cyclic GMP phosphodiesterase in the retina " (see Chapter 23). Its a subunit is designated aj. The related gustducin is found in taste buds. ... 

A FIGURE 4-21 Two-step decoding process for translating nucleic acid sequences in mRNA into amino acid sequences in proteins. StepD An aminoacyl-tRNA synthetase first couples a specific amino acid, via a high-energy ester bond (yellow), to either the 2 or 3 hydroxyl of the terminal adenosine in the... 

The protein kinase with the most potential for food use is probably the adenosine cyclic 3, 5 -monophosphate-dependent protein kinase (cAMPdPK) from bovine cardiac muscle [76,77]. The amino acid sequence of the enzyme has been determined [78,79]. The DNA segment that encodes this kinase has been isolated, cloned, and expressed [80-82]. Thus large quantities of active enzyme could be made economically available if it proves useful in food protein modification. 

Hosono, K., and H. Suzuki Acylpeptides, the Inhibitors of Cyclic Adenosine-3, 5 -monophosphate Phosphodiesterase. II. Amino Acid Sequence and Location of Lactone Linkage. J. Antibiotics 36, 674 (1983). 

A photoreactive nucleotide, 8-bromo-2 -deoxy-adenosine, was incorporated post-synthetically into a DNA sequence (35, Fig. 13) within the previously determined DNA contact site for the transcription factor. Upon irradiation the resulting nitrene cross-linked primarily to the 50-kDa subunit and covalently modified Lys-244. On the other hand, that amino acid residue appeared not... 

All tRNA molecules have the sequence -CCA at the 3 end. This three base sequence is termed the acceptor stem. The aminoacyl-tRNA synthetases catalyze the formation of an ester between the carboxyl group of the amino acid and the 3 -OH of the ribose of the terminal adenosine moiety ... 

A tRNA molecule is specific for a particular amino acid, though there may be several different forms for each amino acid. Although relatively small, the polynucleotide chain may show several loops or arms because of base pairing along the chain. One arm always ends in the sequence cytosine-cytosine-adenosine. The 3 -hydroxyl of this terminal adenosine unit is used to attach the amino acid via an ester linkage. However, it is now a section of the nucleotide sequence that identifies the tRNA-amino acid combination, and not the amino acid itself. A loop in the RNA molecule contains a specific sequence of bases, termed an anticodon, and this sequence allows the tRNA to bind to a complementary sequence of bases, a codon, on mRNA. The synthesis of a protein from the message carried in mRNA is called translation, and a simplified representation of the process as characterized in the bacterium Escherichia coli is shown below. 

First, the amino acid is bound by the enzyme and reacts there with ATP to form diphosphate and an energy-rich mixed acid anhydride (aminoacyl adenylate). In the second step, the 3 -OH group (in other ligases it is the 2 -OH group) of the terminal ribose residue of the tRNA takes over the amino acid residue from the aminoacyl adenylate. In aminoacyl tRNAs, the carboxyl group of the amino acid is therefore esterified with the ribose residue of the terminal adenosine of the sequence. ..CCA-3. ... 

DNA (deoxyribonucleic acid)—Carrier of genetic material that determines inheritance of traits. DNA is in chromosomes in every cell of the body except red blood cells and is copied when cells divide. DNA molecules are shaped like a double helix, and are composed of sequences of four bases adenosine (A), cytosine (C), guanine (G), and thymine (T). The sequence of the bases directs production of particular proteins by determining the sequence of amino acids in proteins. The double-helk structure of DNA helps it transmit genetic information. 

The 5 -terminal residue usually is a guanine nucleotide it is phosphorylated at the 5 -OH. The terminus at the 3 end has the same sequence of three nucleotides in all tRN A s, namely, CCA. The 3 -OH of the adenosine in this grouping is the point of attachment of the tRNA to its specific amino acid ... 

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