China
Africa
Explore chapters and articles related to this topic
Translation
Published in Paul Pumpens, Single-Stranded RNA Phages, 2020
As Capecchi and Webster (1975) emphasized, the determination of the composition of the mRNA fragment, which was protected by the ribosome, could be used to define the position of the mRNA relative to the ribosome in the complex. Thus, after a translocation, one additional codon in the 3′ direction of the mRNA should become resistant to nuclease digestion, but the translocation did not occur until EF-G and GTP were added to the reaction mixture (Gupta et al. 1971). The addition of these components resulted in the conversion of the fMet-alanyl-tRNAala from a puromycin-unreactive state to a puromycin-reactive state, movement of the ribosome one coding unit in the 3′ direction, release of tRNAfmet, and release of EF-G-GDP from the complex. GTP hydrolysis was required for the above reactions. The elongation factor G participated primarily in the release of deacylated tRNA, but the translocation per se was catalyzed by the 50S ribosomal subunit (Tanaka et al. 1971). The EF-Ts was bound to neither the ribosome nor the ternary complex EF-Tu-GTP-aa-tRNA, but it was involved in the release of GDP from the EF-Tu-GDP complex, resulting in an EF-TuTs complex. In the absence of EF-Ts, the action of EF-Tu was stoichiometric rather than catalytic, because EF-Tu became trapped in the EF-Tu-GDP complex released from the ribosome.
Three-Dimensional Structure of p21 and Its Implications
Published in Juan Carlos Lacal, Frank McCormick, The ras Superfamily of GTPases, 2017
Since p21 and EF-Tu with only limited similarity in the primary sequence, have very similar structures in their G domain we can predict that all the GNB proteins with the conserved sequence elements mentioned above have the same overall tertiary structure as the ras-p21 protein. The small GNB proteins, which have primary sequence homologies to p21 in the order of 30 to 80% also consist of only the G domain. The α-subunits of heterotrimeric G proteins, which have a molecular mass of between 45 and 50 kDa, elongation factor Tu (and its eukaryotic homolog EF1) with a molecular mass around 45 kDa, and the elongation factor G (or the eukaryotic homolog EF2) with a molecular mass around 80 kDa must have one or more additional domains which are needed for the particular function of this protein.
Fusidate Sodium
Published in M. Lindsay Grayson, Sara E. Cosgrove, Suzanne M. Crowe, M. Lindsay Grayson, William Hope, James S. McCarthy, John Mills, Johan W. Mouton, David L. Paterson, Kucers’ The Use of Antibiotics, 2017
There are several mechanisms recognized that cause resistance to fusidic acid. One class, FusA, is associated with mutations in fusA that reduce the affinity of fusidic acid for its target elongation factor G (EF-G) on the ribosome (Hansson et al., 2005; Besier et al., 2007). Mutations in fusA causing fusidic acid resistance in S. aureus or in S. epidermidis were shown to result in considerable loss of fitness in such strains (Besier et al., 2005; Gustafsson et al., 2003). In S. aureus, however, fitness-compensating mutations readily occurred (Besier et al., 2005). Mutations in fusA can also cause resistance to fusidic acid in Salmonella spp. (Macvanin et al., 2004). The second class, FusB, until now the most prevalent, is associated with a 21-kB plasmid that carries the fusB gene (O’Brien et al., 2002). This gene encodes an inducible protein that somehow protects EF-G against fusidic acid. FusB has been found to be prevalent in epidemic fusidic acid–resistant S. aureus causing impetigo (O’Neill et al., 2004). In addition, fusC and fusD are two homologs of fusB that have been found on the chromosome of S. aureus and Staphylococcus saprophyticus (O’Neill et al., 2007b). So far, fusB and fusC appear to be the most common fusidic acid resistance determinants in both methicillin-resistant Staphylococcus aureus (MRSA) in Europe and in coagulase-negative staphylococci in China, in both cases indicative of wide horizontal spread of these genes among most staphylococcal species (McLaws et al., 2011; Hung et al., 2015). FusE refers to a fusidic acid–resistance mechanism in S. aureus that phenotypically results in the appearance of small colony variants. It is due to mutations in rplF encoding for ribosomal protein L6. These can be auxotrophic for either hemin or menandione and may also be selected by aminoglycosides, showing that other antibiotics can select for fusidic acid resistance (Norström et al., 2007). Another fusidic acid–resistance mechanism, FusF, was added to the list in 2015 (Chen et al., 2015). It was found in Staphylococcus cohnii subsp. cohnii and subsp. urealyticus, which have MICs of 0.125–4 mg/l and 4–16 mg/l for the two subspecies, respectively. Each of the two subspecies already contains the fusA gene, whereas the fusF element showed 50–71% nucleotide sequence similarity to fusB, and its fusidic acid interaction was proven by cloning experiments (Chen et al., 2015). It is therefore thought to interact with the FusB-family proteins and EF-G (Chen et al., 2015).
The pharmacology of antibiotic therapy in hidradenitis suppurativa
Published in Expert Review of Clinical Pharmacology, 2020
Claudio Marasca, Paolo Tranchini, Vincenzo Marino, Maria Carmela Annunziata, Maddalena Napolitano, Davide Fattore, Gabriella Fabbrocini
Fusidic acid is a selective antibiotic that inhibits protein synthesis by preventing the turnover of elongation factor G (EF-G) from the ribosome. Pharmacokinetic and pharmacodynamic studies have shown that fusidic acid reaches a high antimicrobial concentration in deep skin layers after topical application both on the intact or the damaged epidermis. In its different topical formulations, it showed to be very effective in managing skin infections, and it was reported a high bactericidal activity against many pathogens such as Staphylococcus aureus (including penicillin-resistant strains, methicillin, cloxacillin, and ampicillin), Streptococcus pyogenes, Staphylococcus epidermidis, Propionibacterium acnes, Clostridia, and Corynebacteria [85]. Although these features make fusidic acid specifically useful in the treatment of skin condition, in literature there is only few case report about its use in hidradenitis suppurativa. In a recent prospective study on 627 patients affected by axillary hidradenitis (stage I), a protocol based on frequent washing, antibacterial soaps, and 2% fusidic acid has been used as a conservative treatment: 73.5% of patients had complete healing within two weeks, 20.3% within three weeks,6.2% within four weeks. The recurrence rate was 5.9% in which all patients were retreated conservatively and had complete healing, none required surgical intervention [86]
A comparative review of current topical antibiotics for impetigo
Published in Expert Opinion on Drug Safety, 2021
Eugenio Galindo, Adelaide A Hebert
Fusidic acid was initially isolated in 1962 by Godtfredsen et al. from a culture containing Fusidium coccineum [24]. It belongs to the group of fusidanes and has an asteroid-type structure similar to other antibiotics produced by fungi but it does not possess any steroid activity. The asteroid-type structure is believed to be responsible for the steroid-like high penetration [25]. Fusidic acid functions through inhibition of bacterial protein synthesis via disruption of elongation factor G during translocation on the ribosome which is involved in peptide elongation through a GTPase [26]. Fusidic acid has shown antibacterial activity against gram positive bacteria such as S. aureus and S. pyogenes [27,28]
A review of antibiotics and psoriasis: induction, exacerbation, and amelioration
Published in Expert Review of Clinical Pharmacology, 2019
By binding on the elongation factor G (EF-G) and preventing EF-G turnover, fusidic acid inhibits bacterial protein synthesis. It mainly has effect on gram-positive cocci. Plaque psoriasis: previous promising and opposite reports [25–28] of fusidic acid in psoriasis treatment had led to a double-blind controlled trial (n = 20). Patients with recently overt or hidden infections were all excluded. The result showed no significant difference of clearing psoriasis in active treated group compared with placebo [29].