The site-specific incorporation of the noncanonical amino acid (ncAA) into proteins via genetic code expansion (GCE) has enabled development new and powerful ways to learn, regulate, evolve biological functions in vivo . However, cellular biosynthesis ncAA-containing with high efficiency fidelity is a formidable challenge. In this review, we summarize up-to-date progress towards improving ortho...

AGA and AGG codons for arginine are the least used codons in Escherichia coli, which are encoded by a rare tRNA, the product of the dnaY gene. We examined the positions of arginine residues encoded by AGA/AGG codons in 678 E. coli proteins. It was found that AGA/AGG codons appear much more frequently within the first 25 codons. This tendency becomes more significant in those proteins containing...

b ackground: due to the lack of a suitable and economic test for the analysis of the polymorphism at codon 167, we developed a new pcr-rflp technique, based on a modified forward primer (ut- hc167 mf-primer), to identify simultaneously the snps at codons 167 and 200 of isotype 1 β-tubu- lin gene of haemonchus contortus . m ethods: there already are several safe and easy methods for identificati...

patients and methods in this study, 87 specimens from iranian patients were amplified using nested pcr amplification of the ul97 gene. sequence analyses of products were performed for identifying the mutated codons. results the present study show that the most frequent gcv-resistant mutations occurred in codons a594v (26.43%), h520q (18.39%), and m460v (13.79%), consequently occurring at a low ...

In this paper we assemble a few ingredients that are remotely connected to each other, but governed by the rule of coding theory ([1], [12]) and formal language theory, i.e. cyclic codes and DNA codes. Our interest arose from the remark that there exist both linear and circular DNAs in higher living organisms. We state the theory of codes in a wide sense due to [1] in order to understand the ci...

An attempt is made to answer the question posed by the title of this paper. First we show that in primitive self-replicating oligoribotide systems, selection depended from the very start on the existence of 4 kinds of ribotides, forming 2 complementary pairs. Further selection required that the condensation reactions involving the two last positions of the 3'-end of a growing oligoribotide frag...

DNATagger is a web-based tool for coloring and editing DNA, RNA and protein sequences and alignments. It is dedicated to the visualization of protein coding sequences and also protein sequence alignments to facilitate the comprehension of evolutionary processes in sequence analysis. The distinctive feature of DNATagger is the use of codons as informative units for coloring DNA and RNA sequences...

The precision with which individual termination codons in mRNA are recognized by protein release factors (RFs) has been measured and compared with the decoding of sense codons by tRNA. An Escherichia coli system for protein synthesis in vitro with purified components was used to study the accuracy of termination by RF1 and RF2 in the presence or absence of RF3. The efficiency of factor-dependen...

Most amino acids are encoded by more than one codon. These synonymous codons are not used with equal frequency: in every organism, some codons are used more commonly, while others are more rare. Though the encoded protein sequence is identical, selective pressures favor more common codons for enhanced translation speed and fidelity. However, rare codons persist, presumably due to neutral drift....