User:Fatin Hamd/sandbox

23s rRNA Functions[edit source]
In general, rRNA has an essential function of peptidyl transferase, the stimulating core of the ribosome plays role in the peptide bond configuration. Both peptidyl-tRNA and aminoacyl-tRNA are important for synthesizing protein and transpeptidation response. However, 23S rRNA positions which are G2252, A2451, U2506, and U2585 have a significant function for tRNA binding in P site of the large ribosomal subunit. These modification nucleotides in site P can inhibit peptidyl-tRNA from binding and also remains U2555 modification intervene with transferring peptidyl-tRNA to puromycin.Furthermore, the chemical modification of half of these positions G2251, G2253, A2439, and U2584 can not prevent the tRNA binding. Peptidyl-tRNA of 50s subunits which binds to the P site preserve eight positions of 23S rRNA from chemical modification. On the other hand, 23S rRNA impacts on mutation for cell growth. Mutations A1912G, A1919G and Ψ1917C have a powerful growth phenotypes and they prevent translation while mutation A1916G has a simple growth phenotype and it leads to defect in the 50S subunits. Fatin Alhawti--Fatin Hamd (talk) 03:05, 15 October 2018 (UTC)

Mutation in 23S rRNA and Linezolid relationship[edit source]
There is a linear resistance that have emanated from the laboratory selection tests in differeny organisms showing a number of 23S rRNA mutations in the peptidyl transferase loop. The results show mutations of the organisms in both nucleotides away from the binding pocket and directly in the linezolid link positions such as 2061,2576,2608,2453, and 2062. From the conclusions, G2576U mutation takes place mostly to the linezolid-resistant isolates. Other mutations associated with linezolid resistance include RSA 23S, L3, and L4, which are ribosomal proteins, although there is little evidence of cause-and-effect relationship in the evidence.

i-Single 23S Rrna Mutations related with domain in the PTC region
Antibiotics are usually particular to the ribosomes of a single or two domains or life and some global antibiotics block ribosomes from three domains of life. The success of ribosomal antibiotics depend on the way bacterial ribosomes are selected and fitted with mammals. Peptidyl transferase of bacterial ribosomes relates with linezolid and should not be lower or less than eukaryotic cytosolic ribosomes. Drug binding and susceptibility depend on the bacteria ribosome and affects the shapes of the nucleotides of the ligament of the body cells. The other layer of cucleotide is 2453 and the third nucleotide 2032 and 2499 that differs between human and bacteria cytosolic rRNA.

ii-Single and double 23S Rrna mutations areas relevant with antibiotic resistance
From the experiments, mutations seen at the 12 23S rRNA indicate conferment of linezolid resistance. Four sinale 23S rRNA nucleotides namely G2505A, C2612A, A2503G, and C2571G were associated with linezolid resistance without genetic evidence of resistance. In the tests, the A2503G mutation and G2576U were detected in S.aureusand C2571G and A1743U derecred in S.pneumoniaestrains though there was low linezolid sensitivities. The A2503U mutation in bacterial ribosomes is related to lincomycin in Mycoplasma galliswpticum and with lower susceptibility to tiamulin, valnemulin, valnemulin, and chroramphenicol. Additionally, florfenicol susceptibility is reduced by the mutation. The mutation G2576U is the most significant 23S rRNA mutations detected in linezolid resistance clinical isolates. Single mutations of G2032A, C2055A, C2499A, U2504G and A2572U were either linked or shown to give linezolid antibiotic resistance or other PTC antibiotics to compare their effects with those mutations in M.smegmatis.In addition, double mutations of 23S rRNA related with antibiotic resistance, single mutations cannot give resistant alone but they contribute to resistance with other mutant. G2032A-C2499A, G2032A-U2504G, C2055A-U2504G and C2055A-A2572U are combination of double mutation which have been observed in tiamulin resistant Brachyspira hyodysenteriae isolates. All of the double mutations exhibit a significant increase in MICs compared to the wild type and single mutant strains. Therefore, there are effected on linezolid resistance as double mutations give MICs higher linezolid than single mutation. The G2032A-U2504G an 8-fold shows increased in MIC linezolid related to U2504G single mutant. C2055A-U2504G shows a 4-fold increase in linezolid, which is related to the single mutant U2504G. C2055A-A2572U mutation shows 16-fold increase in MIC linezolid related to single mutant A2572U. Also, there is effects on clindamycin resistance along with C2055A-A2572U mutation, where MIC is increased by 16 fold to 32 fold for wild type and C2055A and A2572 mutant. Additionally, there was an increase and decrease in MICs of Valnemulin and chloramphenicol for double mutant related to single mutants. .