Several methanogenic archaea lack cysteinyl–transfer RNA (tRNA) synthetase (CysRS), the essential enzyme that provides Cys-tRNA Cys for translation in most organisms. Partial purification of corresponding activity from Methanocaldococcus jannaschii indicated tRNA becomes acylated with O -phosphoserine (Sep) but not cysteine. Further analyses identified a class II–type -phosphoseryl-tRNA (SepRS) and Sep-tRNA:Cys-tRNA synthase (SepCysS). SepRS specifically forms Sep-tRNA , which is then...

Dynamic light scattering (DLS) analyses are routinely used in biology laboratories to detect aggregates macromolecular solutions, determine the size of proteins, nucleic acids, and complexes or monitor binding ligands. This article is written for graduate undergraduate students with access DLS faculty members who wish incorporate into a lab activity, practical course research. It reviews basic concepts measurements addresses four critical aspects analysis interpretation results. To ensure...

Multiple peptide resistance (MprF) virulence factors control cellular permeability to cationic antibiotics by aminoacylating inner membrane lipids. It has been shown previously that one class of MprF can use Lys-tRNA(Lys) modify phosphatidylglycerol (PG), but the mechanism recognition and possible role other MprFs are unknown. Here, we used an in vitro reconstituted lipid aminoacylation system investigate two phylogenetically distinct paralogs (MprF1 MprF2) found bacterial pathogen...

Accurate selection of amino acids is essential for faithful translation the genetic code. Errors during acid are usually corrected by editing activity aminoacyl-tRNA synthetases such as phenylalanyl-tRNA (PheRS), which edit misactivated tyrosine. Comparison cytosolic and mitochondrial PheRS from yeast Saccharomyces cerevisiae suggested that organellar protein might lack activity. Yeast was found to contain an site, upon disruption abolished both cis trans Tyr-tRNA(Phe). Wild-type lacked...

Aminoacylphosphatidylglycerol synthases (aaPGSs) are multiple peptide resistance factors that transfer amino acids from aminoacyl-tRNAs to phosphatidylglycerol (PG) in the cytoplasmic membrane. Aminoacylation of PG is used by bacteria decrease net negative charge cell envelope, diminishing affinity for charged molecules and allowing adaptation environmental changes. Lys-PGS, which transfers lysine PG, essential virulence certain pathogens, providing both host cationic antimicrobial peptides...

ABSTRACT Elongation factor P (EF-P) is posttranslationally modified at a conserved lysyl residue by the coordinated action of two enzymes, PoxA and YjeK. We have previously established importance this modification in Salmonella stress resistance. Here we report that, like poxA yjeK mutants, strains lacking EF-P display increased susceptibility to hypoosmotic conditions, antibiotics, detergents enhanced resistance compound S -nitrosoglutathione. The phenotypes are largely explained membrane...

Protein synthesis has an overall error rate of approximately 10 -4 for each mRNA codon translated. The fidelity translation is mainly determined by two events: cognate amino acid:tRNA pairs aminoacyl-tRNA synthetases (aaRSs) and accurate selection aminoacyl-tRNAs (aa-tRNAs) the ribosome. To ensure faithful aa-tRNA synthesis, many aaRSs employ a proofreading (“editing”) activity, such as phenylalanyl-tRNA (PheRS) that hydrolyze mischarged Tyr-tRNA Phe . Eukaryotes maintain distinct PheRS...

Protein synthesis requires the pairing of amino acids with tRNAs catalyzed by aminoacyl-tRNA synthetases. The synthetases are highly specific, but errors in acid selection occasionally made, opening door to inaccurate translation genetic code. fidelity protein is maintained editing activities synthetases, which remove noncognate from before they delivered ribosome. Although has been described numerous reaction mechanism unknown. To define editing, phenylalanyl-tRNA synthetase was used...

The Trojan horse antibiotic albomycin, produced by Streptomyces sp. strain ATCC 700974, contains a thioribosyl nucleoside moiety linked to hydroxamate siderophore through serine residue. seryl structure (SB-217452) is potent inhibitor of seryl-tRNA synthetase (SerRS) in the pathogenic bacterium Staphylococcus aureus, with 50% inhibitory concentration (IC(50)) approximately 8 nM. In albomycin-producing sp., bacterial SerRS homolog (Alb10) was found be encoded biosynthetic gene cluster...

Faithful protein synthesis relies on a family of essential enzymes called aminoacyl-tRNA synthetases, assembled in piecewise fashion. Analysis the completed archaeal genomes reveals that all archaea possess asparaginyl-tRNA synthetase (AsnRS) also display second ORF encoding an AsnRS truncated from its anticodon binding-domain (AsnRS2). We show herein Pyrococcus abyssi AsnRS2, contrast to AsnRS, does not sustain Asn but is instead capable converting aspartic acid into asparagine. Functional...

Listeria monocytogenes is an intracellular, foodborne gastrointestinal pathogen that primarily responsible for causing listeriosis or food poisoning in otherwise healthy individuals. Infections arise during pregnancy within immune compromised individuals are much more serious resulting the risk of fetal termination fatality postpartum former and septicemia meningitis with a 20% rate latter. While roles internalin proteins listeriolysin-O infection process well characterized, specific...

Thermus thermophilus possesses two aspartyl-tRNA synthetases (AspRSs), AspRS1 and AspRS2, encoded by distinct genes. Alignment of the protein sequences with AspRSs other origins reveals that structural features eubacterial AspRSs, whereas AspRS2 is structurally related to archaebacterial AspRSs. The dissimilarity between thermophilic correlated functional divergences. aspartylates tRNAAsp tRNAAsp, tRNAAsn similar efficiencies. Since Asp bound on converted into Asn a tRNA-dependent aspartate...

In most prokaryotes Asn-tRNAAsn and Gln-tRNAGln are formed by amidation of aspartate glutamate mischarged onto tRNAAsn tRNAGln, respectively. Coexistence in the organism Asp-tRNAAsn Glu-tRNAGln homologous does not, however, lead to erroneous incorporation Asp Glu into proteins, since EF-Tu discriminates misacylated tRNAs from correctly charged ones. This property contrasts with canonical function EF-Tu, which is non-specifically bind aa-tRNAs, as well heterologous species vitro...

Human mitochondrial tRNA (hmt-tRNA) mutations are associated with a variety of diseases including myopathies, diabetes, encephalopathies, and deafness. Because the current understanding precise molecular mechanisms these is limited, there no efficient method to treat their diseases. Here, we use known in hmt-tRNA(Phe) investigate that lead malfunctions. We tested impact on aminoacylation, structure, translation elongation-factor binding. The majority mutants were pleiotropic, exhibiting...

Insertion of lysine during protein synthesis depends on the enzyme lysyl-tRNA synthetase (LysRS), which exists in two unrelated forms, LysRS1 and LysRS2. has been found most archaea some bacteria, LysRS2 eukarya, a few archaea, but proteins are almost never together single organism. Comparison structures complexed with suggested significant differences their potential to bind analogues backbone replacements. One such naturally occurring compound, metabolic intermediate S -(2-aminoethyl)- l...