Sequence information complementary

Information within the single strand of RNA is contained in its sequence ( primary strucmre ) of purine and pyrimidine nucleotides within the polymer. The sequence is complementary to the template strand of the gene from which it was transcribed. Because of this... 

Figure 4.2 Generalized outline of a gene chip. In this example, short oligonucleotide sequences are attached to the anchoring surface (only the outer rows are shown). Each probe displays a different nucleotide sequence, and the sequences used are usually based upon genome sequence information. The sequence of one such probe is shown as AGGCA. By incubating the chip with, for example, total cellular mRNA under appropriate conditions, any mRNA with a complementary sequence (UCCGU in the case of the probe sequence shown) will hybridize with the probes. In reality, probes will have longer sequences than the one shown above...

Transcription. For expression of a gene—i. e., synthesis of the coded protein—the DNA sequence information has to be converted into a protein sequence. As DNA itself is not involved in protein synthesis, the information is transferred from the nucleus to the site of synthesis in the cytoplasm. To achieve this, the template strand in the relevant part of the gene is transcribed into an RNA (hnRNA). The sequence of this RNA is thus complementary to that of the template strand (3), but— with the exception of the exchange of thy-... 

The actual information transfer is based on the interaction between the mRNA codons and another type of RNA, transfer RNA (tRNA see p. 82). tRNAs, of which there are numerous types, always provide the correct amino acid to the ribosome according to the sequence information in the mRNA. tRNAs are loaded with an amino acid residue at the 3 end. Approximately in the middle, they present the triplet that is complementary to each mRNA codon, known as the anticodon (GAA in the example shown). If the codon UUC appears on the mRNA, the anticodon binds a molecule of Phe-t-RNA to the mRNA (5) and thus brings the phenylalanine residue at the other end of the molecule into a position in which it can take over the growing polypeptide chain from the neighboring tRNA (6). 

K. Hakansson, H. J. Cooper, M. R. Emmett, C. E. Costello, A. G. Marshall, and C. L. Nilsson, Electron capture dissociation and infrared multiphoton dissociation MS/MS of an N-glycosylated tryptic peptide to yield complementary sequence information, Anal. Chem., 73 (2001) 4530-4536. 

The genetic information in a gene is copied (transcribed) into a messenger RNA molecule (mRNA), preserving the sequence by complementary base-pairing. The introns are cut and the mRNA molecule is transported into the cytoplasm where it directs the synthesis of protein at the ribosomes. The sequence of bases is translated into a sequence of amino acid residues by a triplet code wherein three bases specify one amino acid. 

For sequencing such proteins, a complementary experimental approach based on recombinant DNA technology is often more efficient. As will be discussed in Chapter 6. long stretches of DNA can be cloned and sequenced, and the nucleotide sequence directly reveals the amino acid sequence of the protein encoded by the gene (Figure 4.29). Recombinant DNA technology is producing a wealth of amino acid sequence information at a remarkable rate. 

Particle beam LC/FT-IR and LC/MS spectrometries provide both different and complementary information. LC/MS measurements provide fragment identity and sequence information through an accurate determination of molecular mass. PB LC/FT-IR spectrometry measurements provide information on the solution structure of the peptide that includes residual or chromatographically induced secondary stmcture and aggregation, as well as information on the presence of some amino acid functionalities. The PB technique is especially useful with larger peptides which posses formal secondary structure. 

It is unusual for either CID or ETD to provide complete sequence information from any one peptide but the use of both techniques provides complementary information, which can gready extend the sequence coverage (Table 4). In addition, because the energy from the ETD process is directed into cleaving the Ca—N bond, the labile PTMs are preserved and their location in the peptide sequence can then be determined90 (see also discussion in Section 9.10.3.2.6 on the use of CID/IRMPD and ECD/ETD for protein/peptide sequencing, and Table 4). 

An anticodon is a sequence of three nucleotides in a transfer RNA (tRNA) that is complementary to a codon of messenger RNA (mRNA). The relationship between codons and the amino acids they code for is called the genetic code. The process of converting mRNA sequence information to the amino acid sequence of a protein is called translation. 

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