Nucleotide, defined

The 3x10 base pairs of DNA in humans are organized into the haploid complement of 23 chromosomes. The exact sequence of these 3 billion nucleotides defines the uniqueness of each individual. 

The template-binding step involves interaction of the holoenzyme, through its cr subunit, with the promoter to give the open promoter complex, as already described. Initiation of the RNA chain can then proceed through the formation of the first phosphodiester bond between ATP (or GTP) and the next nucleotide defined by the template to yield a dinucleoside tetraphosphate ... 

Assuming that the first three nucleotides define the first codon, what is the peptide sequence coded for by (a) UAAUAGUGAUAA, (b) UUAUUGCUUCUCCUACUG ... 

The three-dimensional structures of GTPyS-Gj-al of Coleman a of the trans-ducin a-GDP-AlF4 complex by Sondek et and Gj -a hum Paul Sigler s laboratory, ref. 84, show how the crucial Arg-residue contacts the y-phosphate of GTP directly. Thus, the presence or absence of the y-phosphate in the guanine nucleotide defines the active or inactive state of a G a-subunit. 

The sequence or order of the nucleotides defines the primary structure of DNA and RNA. The nucleotides of the polymer are linked by phosphodiester bonds... 

For example, a polypeptide is synthesized as a linear polymer derived from the 20 natural amino acids by translation of a nucleotide sequence present in a messenger RNA (mRNA). The mature protein exists as a weU-defined three-dimensional stmcture. The information necessary to specify the final (tertiary) stmcture of the protein is present in the molecule itself, in the form of the specific sequence of amino acids that form the protein (57). This information is used in the form of myriad noncovalent interactions (such as those in Table 1) that first form relatively simple local stmctural motifs (helix... 

Mutagenic PGR. More recently, methods have been developed to use the PGR reaction to randomly mutagenize a defined sequence (25). The Taq polymerase used in PGR misincorporates nucleotides in a random fashion if manganese dichloride [7773-01 -5] MnGl2, is included in the reaction buffer during PGR. The Hbrary of mutagenized PGR products can be screened for the desired phenotype. 

Cellular Protein Biosynthesis. The process of cellular protein biosynthesis is virtually the same in all organisms. The information which defines the amino acid sequence of a protein is encoded by its corresponding sequence of DNA (the gene). The DNA is composed of two strands of polynucleotides, each comprising some arrangement (sequence) of the four nucleotide building blocks of the nucleic acids adenine (A), thymine (T),... 

LDH-x is one of the best characterized antigens and its amino acid sequence is known. A synthetic peptide based on a portion of the molecule has been shown to reduce fertUity in laboratory animals. The nucleotide sequence coding for human LDH-x has been defined and engineered into an expression vector system (121). 

Vitamin B12 (Fig. 1) is defined as a group of cobalt-containing conoids known as cobalamins. The common features of the vitamers are a corrin ting (four reduced pyrrole rings) with cobalt as the central atom, a nucleotide-like compound and a variable ligand. Vitamin B12 is exceptional in as far as it is the only vitamin containing a metal-ion. The vitamers present in biological systems are hydroxo-, aquo-, methyl-, and 5 -deoxyadenosylcobalamin. 

In both intermediate and maximum rates of respiration, control is distributed between several different steps, including the activity of the adenine nucleotide translocator (Groen et al., 1983). It is now recognized that the idea of a simple rate-limiting step for a metabolic pathway is simplistic and that control is shared by all steps although to different extents (Kacserand Bums, 1978 Fell, 1992). Each step in a pathway has a flux control coefficient (FCC) defined as ... 

Thus three lines of evidence define the rapidly dissociating receptor as the LR complex. Conditions known to uncouple R from G--first, guanine nucleotide and second, pertussis toxin—produce LR third, reconstitution of G protein restores receptor affinity, sensitivity to guanine nucleotide, and effector activation. In this sense, the ligand and binding behavior of this system is analogous to that of the beta-adrenergic receptor, where the LR and LRG complexes have already been studied with purified proteins and reconstituted membrane preparations (2,i0). 

Oligonucleotide A short, defined sequence of nucleotides joined together in the typical phosphodi-ester linkage. 

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