Stringent Nucleotide Recognition by the Ribosome at the Middle Codon Position

Background: Tuberculosis (TB) is fatal and life threatening infectious disease. The transmission rate of tuberculosis is very high. Various drugs are used as treatment for TB. Recently it has been observed that one of the most important factor for fast TB spread is development of anti-TB drug resistant mycobacterium tuberculosis (MTB). Various combination of drugs like isoniazid (INH), rifampicin (RIF), Streptomycin(SM), pyrazinamide (PZA) or ethambutol (EMB) are in global use for TB treatment. Improper usage of these drugs makes the person prone to develop anti-TB drug resistant tuberculosis. Aim: To evaluate association of embB gene with ethambutol resistance in Mycobacterium Tuberculosis. Methods: 104 Specimens of sputum from suspected tuberculosis patients were processed for inoculation in Lowenstein J Medium after it has been decontaminated properly. Kit method by using QIAamp DNA Mini kit was utilized for extraction of DNA. Then region from base 6953 to 10249 of embB gene was amplified through PCR and then followed by sequencing with the aid of softwares blast2seq and ClustalW2. Three primer sets were utilized to amplify embB gene. Ethambutol (EMB) Resistant MTB specimens were processed to study mutation in embB gene. Results: Out of the total 104 sputum specimens, 14 samples were found to have ethambutol resistance. These 14 samples were then processed for mutational analysis. DNA sequence analysis of these 14 samples confirmed embB gene mutation in 10 samples. Mutational analysis revealed that 08 samples showed mutation at codon 306 and two samples showed mutation at 319 codon. The reported mutation Methionine →Isoleucine was seen in 07 samples with ATG codon replaced by ATA codon at codon position 306. One sample showed mutation as Methionine →Isoleucine with ATG codon replaced by ATC codon at codon position 306. Two samples showed mutation as Tyrosine →Serine with TAT codon replaced by TCT at 319 codon position in embB gene. Conclusion: This study concludes that mutation of certain genes particularly point mutation of embB gene at codon 306 and 319 is associated with drug resistance of ethambutol in ethambutol resistant mycobacterium tuberculosis patients. Keywords: Ethambutol, embB gene, Mycobacterium tuberculosis.

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Using mitoribosomal profiling to investigate human mitochondrial translation

Wellcome Open Research ◽

10.12688/wellcomeopenres.13119.2 ◽

2018 ◽

Vol 2 ◽

pp. 116

Author(s):

Fei Gao ◽

Maria Wesolowska ◽

Reuven Agami ◽

Koos Rooijers ◽

Fabricio Loayza-Puch ◽

...

Keyword(s):

Gene Expression ◽

Protein Synthesis ◽

Codon Position ◽

Mitochondrial Protein ◽

Mitochondrial Protein Synthesis ◽

Mitochondrial Translation ◽

Base Pairs ◽

Suboptimal Structure ◽

Human Counterpart ◽

Steady State Levels

Background: Gene expression in human mitochondria has various idiosyncratic features. One of these was recently revealed as the unprecedented recruitment of a mitochondrially-encoded tRNA as a structural component of the large mitoribosomal subunit. In porcine particles this is mt-tRNAPhe whilst in humans it is mt-tRNAVal. We have previously shown that when a mutation in mt-tRNAVal causes very low steady state levels, there is preferential recruitment of mt-tRNAPhe. We have investigated whether this altered mitoribosome affects intra-organellar protein synthesis. Methods: By using mitoribosomal profiling we have revealed aspects of mitoribosome behaviour with its template mt-mRNA under both normal conditions as well as those where the mitoribosome has incorporated mt-tRNAPhe. Results: Analysis of the mitoribosome residency on transcripts under control conditions reveals that although mitochondria employ only 22 mt-tRNAs for protein synthesis, the use of non-canonical wobble base pairs at codon position 3 does not cause any measurable difference in mitoribosome occupancy irrespective of the codon. Comparison of the profile of aberrant mt-tRNAPhe containing mitoribosomes with those of controls that integrate mt-tRNAVal revealed that the impaired translation seen in the latter was not due to stalling on triplets encoding either of these amino acids. The alterations in mitoribosome interactions with start codons was not directly attributable to the either the use of non-cognate initiation codons or the presence or absence of 5’ leader sequences, except in the two bicistronic RNA units, RNA7 and RNA14 where the initiation sites are internal. Conclusions: These data report the power of mitoribosomal profiling in helping to understand the subtleties of mammalian mitochondrial protein synthesis. Analysis of profiles from the mutant mt-tRNAVal cell line suggest that despite mt-tRNAPhe being preferred in the porcine mitoribosome, its integration into the human counterpart results in a suboptimal structure that modifies its interaction with mt-mRNAs.

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Consistent Clustering Pattern of Prokaryotic Genes Based on Base Frequency at the Second Codon Position and its Association with Functional Category Preference

Interdisciplinary Sciences Computational Life Sciences ◽

10.1007/s12539-021-00493-w ◽

2021 ◽

Author(s):

Yan-Ting Jin ◽

Cong Ma ◽

Xin Wang ◽

Shu-Xuan Wang ◽

Kai-Yue Zhang ◽

...

Keyword(s):

Protein Function ◽

Codon Position ◽

Systematic Investigation ◽

Functional Category ◽

Gene Clustering ◽

Base Frequency ◽

Significant Difference ◽

Prokaryotic Genomes ◽

Functional Classes ◽

Clustering Pattern

AbstractIn 2002, our research group observed a gene clustering pattern based on the base frequency of A versus T at the second codon position in the genome of Vibrio cholera and found that the functional category distribution of genes in the two clusters was different. With the availability of a large number of sequenced genomes, we performed a systematic investigation of A2–T2 distribution and found that 2694 out of 2764 prokaryotic genomes have an optimal clustering number of two, indicating a consistent pattern. Analysis of the functional categories of the coding genes in each cluster in 1483 prokaryotic genomes indicated, that 99.33% of the genomes exhibited a significant difference (p < 0.01) in function distribution between the two clusters. Specifically, functional category P was overrepresented in the small cluster of 98.65% of genomes, whereas categories J, K, and L were overrepresented in the larger cluster of over 98.52% of genomes. Lineage analysis uncovered that these preferences appear consistently across all phyla. Overall, our work revealed an almost universal clustering pattern based on the relative frequency of A2 versus T2 and its role in functional category preference. These findings will promote the understanding of the rationality of theoretical prediction of functional classes of genes from their nucleotide sequences and how protein function is determined by DNA sequence. Graphical abstract

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The first 3′:5′-cyclic nucleotide–amino acid complex:L-His–cIMP

Acta Crystallographica Section C Crystal Structure Communications ◽

10.1107/s0108270112030041 ◽

2012 ◽

Vol 68 (8) ◽

pp. o311-o316 ◽

Cited By ~ 4

Author(s):

Katarzyna Ślepokura

Keyword(s):

Crystal Structure ◽

Amino Acid ◽

Cyclic Nucleotide ◽

Phosphate Group ◽

Specific Amino Acid ◽

Π Stacking ◽

Cyclic Phosphate ◽

Nucleotide Recognition ◽

Group Play ◽

Phosphate Groups

In the crystal structure of the L-His–cIMP complex,i.e.L-histidinium inosine 3′:5′-cyclic phosphate [systematic name: 5-(2-amino-2-carboxyethyl)-1H-imidazol-3-ium 7-hydroxy-2-oxo-6-(6-oxo-6,9-dihydro-1H-purin-9-yl)-4a,6,7,7a-tetrahydro-4H-1,3,5,2λ5-furo[3,2-d][1,3,2λ5]dioxaphosphinin-2-olate], C6H10N3O2+·C10H10N4O7P−, the Hoogsteen edge of the hypoxanthine (Hyp) base of cIMP and the Hyp face are engaged in specific amino acid–nucleotide (His...cIMP) recognition,i.e.by abutting edge-to-edge and by π–π stacking, respectively. The Watson–Crick edge of Hyp and the cIMP phosphate group play a role in nonspecific His...cIMP contacts. The interactions between the cIMP anions (anti/C3′–endo/trans–gauche/chair conformers) are realized mainly between riboses and phosphate groups. The results for this L-His–cIMP complex, compared with those for the previously reported solvated L-His–IMP crystal structure, indicate a different nature of amino acid–nucleotide recognition and interactions upon the 3′:5′-cyclization of the nucleotide phosphate group.

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Major Revisions in Arthropod Phylogeny Through Improved Supermatrix, With Support for Two Possible Waves of Land Invasion by Chelicerates

Evolutionary Bioinformatics ◽

10.1177/1176934320903735 ◽

2020 ◽

Vol 16 ◽

pp. 117693432090373 ◽

Cited By ~ 4

Author(s):

Katherine E Noah ◽

Jiasheng Hao ◽

Luyan Li ◽

Xiaoyan Sun ◽

Brian Foley ◽

...

Keyword(s):

Codon Position ◽

Amino Acid Level ◽

Phylogenetic Reconstruction ◽

Original Data ◽

Data Sets ◽

Multiple Sequence ◽

Protein Coding ◽

Individual Gene ◽

The Third ◽

New Hypothesis

Deep phylogeny involving arthropod lineages is difficult to recover because the erosion of phylogenetic signals over time leads to unreliable multiple sequence alignment (MSA) and subsequent phylogenetic reconstruction. One way to alleviate the problem is to assemble a large number of gene sequences to compensate for the weakness in each individual gene. Such an approach has led to many robustly supported but contradictory phylogenies. A close examination shows that the supermatrix approach often suffers from two shortcomings. The first is that MSA is rarely checked for reliability and, as will be illustrated, can be poor. The second is that, to alleviate the problem of homoplasy at the third codon position of protein-coding genes due to convergent evolution of nucleotide frequencies, phylogeneticists may remove or degenerate the third codon position but may do it improperly and introduce new biases. We performed extensive reanalysis of one of such “big data” sets to highlight these two problems, and demonstrated the power and benefits of correcting or alleviating these problems. Our results support a new group with Xiphosura and Arachnopulmonata (Tetrapulmonata + Scorpiones) as sister taxa. This favors a new hypothesis in which the ancestor of Xiphosura and the extinct Eurypterida (sea scorpions, of which many later forms lived in brackish or freshwater) returned to the sea after the initial chelicerate invasion of land. Our phylogeny is supported even with the original data but processed with a new “principled” codon degeneration. We also show that removing the 1673 codon sites with both AGN and UCN codons (encoding serine) in our alignment can partially reconcile discrepancies between nucleotide-based and AA-based tree, partly because two sequences, one with AGN and the other with UCN, would be identical at the amino acid level but quite different at the nucleotide level.

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Characterization of the Complete Mitochondrial Genome of Fischoederius elongatus Derived from Cows in Shanghai, China

BioMed Research International ◽

10.1155/2020/7975948 ◽

2020 ◽

Vol 2020 ◽

pp. 1-6

Author(s):

Zhaoqing Han ◽

Kun Li ◽

Houqiang Luo ◽

Muhammad Shahzad ◽

Khalid Mehmood

Keyword(s):

Amino Acids ◽

Mitochondrial Genome ◽

Ribosomal Rna ◽

Parasite Species ◽

Codon Position ◽

Complete Mitochondrial Genome ◽

Nucleotide Composition ◽

Protein Coding ◽

Rna Genes

A study was conducted to reveal the characterization of the complete mitochondrial genome of Fischoederius elongatus derived from cows in Shanghai, China. Results indicated that the complete mt genome of F. elongatus was 14,288 bp and contained 12 protein-coding genes (cox1-3, nad1-6, nad4L, atp6, and cytb), 22 transfer RNA genes, and two ribosomal RNA genes (l-rRNA and s-rRNA). The overall A + T content of the mt genome was 63.83%, and the nucleotide composition was A (19.83%), C (9.75%), G (26.43%), and T (44.00%). A total of 3284 amino acids were encoded by current F. elongatus isolate mt genome, TTT (Phe) (9.84%) and TTG (Leu) (7.73%) codon were the most frequent amino acids, whereas the ACC (Thr) (0.06%), GCC (Ala) (0.09%), CTC (Leu) (0.09%), and AAC (Asn) (0.09%) codon were the least frequent ones. At the third codon position of F. elongatus mt protein genes, T (50.82%) was observed most frequently and C (5.85%) was the least one. The current results can contribute to epidemiology diagnosis, molecular identification, taxonomy, genetic, and drug development researches about this parasite species in cattle.

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