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Devising and Synthesis of NEMS and MEMS
Published in Sergey Edward Lyshevski, Nano- and Micro-Electromechanical Systems, 2018
The fundamental question to be examined is how much information is needed to describe the patterns. Messenger RNA (mRNA) carries information specifying amino acid sequences of proteins from DNA to ribosomes. Transfer RNA (tRNA) translates mRNA nucleotide sequences into protein amino acid sequences. Finally, ribosomal RNA (rRNA)and small nuclear RNA (snRNA) play structural and enzymatic roles. In addition to a binding site for mRNA, each ribosome has two binding sites for tRNA. The P site (peptidyl-tRNA site) holds the tRNA carrying the growing polypeptide chain, while the A site (aminoacyl-tRNA site) holds the tRNA carrying the next amino acid to be added to the chain. The ribosome holds the tRNA and mRNA molecules close together, while proteins catalyze the transfer of an amino acid to the carboxyl end of the growing polypeptide chain. The mRNA is moved through the ribosome in the 5` → 3` direction only (ribosome and mRNA move relative to each other unidirectionally, codon by codon). RNA polymerases (enzymes) add nucleotides to the 3” end of the growing polymer, and the RNA molecule elongates in its 5` → 3` direction. Specific sequences of nucleotides along the DNA mark the initiation and termination sites where transcription of a gene begins and ends.
Biomolecular Processing and Molecular Electronics
Published in Sergey Edward Lyshevski, Molecular Electronics, Circuits, and Processing Platforms, 2018
The question of interest is how much information is needed to describe these patterns. Messenger RNA carries information specifying the amino acid sequences of proteins from the DNA to the ribosomes. Transfer RNA (tRNA) translates mRNA nucleotide sequences into protein amino acid sequences. Finally, ribosomal RNA (rRNA) and small nuclear RNA (snRNA) play structural and enzymatic roles. In addition to a binding site for mRNA, each ribosome has two binding sites for tRNA. The P site (peptidyl-tRNA site) holds the tRNA carrying the growing polypeptide chain, while the A site (aminoacyl-tRNA site) holds the tRNA carrying the next amino acid to be added to the chain. The ribosome holds the tRNA and mRNA molecules close together, while proteins catalyze the transfer of an amino acid to the carboxyl end of the growing polypeptide chain. The mRNA is moved through the ribosome in the 5′ → 3′ direction only (ribosome and mRNA move relative to each other unidirectionally, codon by codon). RNA polymerase (enzyme) adds nucleotides to the 3′ end of the growing polymer, and RNA molecule elongates in its 5′ → 3′ direction. Specific sequences of nucleotides along the DNA mark the initiation and termination sites where transcription of a gene begins and ends.
Nanostructured Cellular Biomolecules and Their Transformation in Context of Bionanotechnology
Published in Anil Kumar Anal, Bionanotechnology, 2018
Protein synthesis initiates with the assembly of the translation complex. Ribosome identifies the initiation codon, which is usually AUG (codes for methionine), but GUG, UUG, or AUU may also be used. Among the two methionyl-tRNAMet molecule that translates AUG codons, initiator tRNA is used at the initiation codon. At the end of the initiation step, mRNA is positioned in such a way that the next codon can be translated during the elongation step, the initiator tRNA is attached to P site and A site of ribosome is ready to receive incoming aminoacyl-tRNA. During chain elongation process, tRNA with the correct aminoacyl-tRNA attach into the A site. The peptidyl transferase catalyzes a transfer of the amino acid from the P site to the amino acid at the A site with the formation of peptide bond such that the growing polypeptide chain is covalently attached to the tRNA in the A site, forming a peptidyl-tRNA. The first amino acid on the polypeptide has a free amino group, so it is called the N-terminal and the last amino acid has a free carboxylic group, so it is called the C-terminal. The mRNA shifts by one codon such that two tRNAs at the P and A site translocate. Following this, deaminoacylated tRNA is displaced from P to exit, E site and peptidyl-tRNA is displaced from A to P site. When one of the three stop codons (UAA, UAG, UGA) on the mRNA is reached, tRNA does not recognize these termination codons and release factor causing the hydrolysis of the peptidyl-tRNA releasing polypeptide chain (Moran et al. 2012).
Expedition on surface adsorption of N-nitrosodiethylamine from rubber fumes on blue phosphorene sheets – a first-principles insight
Published in Molecular Physics, 2020
R. Bhuvaneswari, V. Nagarajan, R. Chandiramouli
Now, the two important electronic features, band structure and PDOS spectrum are determined and discussed for the NDE adsorbed BP. Figure 4(a–e) illustrates the band structure and PDOS spectrum for the adsorbed BP cases. The reckoned energy band gap values for B-site, P-site, R-site, T-site and V-site are 0.97, 0.42, 0.48, 0.19 and 0.45 eV, correspondingly. In addition, the PDOS spectrum prevails as an evidence in ensuring the energy gap value and also offers us a way to envision the alteration happening in the prime material upon surface assimilation of target vapour [54,55]. Bands and PDOS maps – (a) B-site, (b) P-site, (c) R-site, (d) T-site and (e) V-site.
Critical evaluation of rate coefficients for hydroxyl radical reactions with antibiotics: A review
Published in Critical Reviews in Environmental Science and Technology, 2018
László Wojnárovits, Tünde Tóth, Erzsébet Takács
The macrolides are highly substituted monocyclic lactones with one or more saccharides glycosidically attached to the hydroxyl groups. Macrolides inhibit protein synthesis in bacteria by reversibly binding to the P site of the 50S unit of the ribosome. They mainly affect Gram-positive cocci and intracellular pathogens such as Mycoplasma, Chlamydia, and Legionella. Their action is primarily bacteriostatic, but at high concentrations may be bactericidal (Tenson, 2003). The pKa values of macrolides are in the 7.5 − 9.2 range (Dodd et al., 2006).