Disease relevance of ECs3554

• Escherichia coli alanyl-tRNA synthetase contains a zinc-binding Cys-Xaa2-Cys-Xaa6-His-Xaa2-His motif that resembles that of retroviral nucleic acid binding proteins [1].
• Although this motif in E. coli alanyl-tRNA synthetase is of a different size than and has only two sequence identities with the analogous motif in yeast aspartyl- and Thermus thermophilus seryl-tRNA synthetases, whose structures are known, the functional consequences of the mutations are explainable in terms of those structures [2].

High impact information on ECs3554

• Class II may also contain AlaRS and GlyRS, because these sequences have a typical motif 3 [3].
• Docking of tRNA(Ala) on AlaRS shows critical contacts with the three domains, consistent with previous mutagenesis and functional data [4].
• Early work on aminoacylation of alanine-specific tRNA (tRNA(Ala)) by alanyl-tRNA synthetase (AlaRS) gave rise to the concept of an early "second genetic code" imbedded in the acceptor stems of tRNAs [4].
• When applied to Escherichia coli alanyl-tRNA synthetase, the assay allowed accurate measurement of aminoacylation of the most deleterious mutants of tRNA(Ala) [5].
• The correlation between functional and structural data suggests that the G.U pair provides a distinctive structure and a point of deformability that allow the tRNA acceptor end to fit into the active site of the alanyl-tRNA synthetase [6].

Chemical compound and disease context of ECs3554

• Previous work showed that the transfer of alanine from Escherichia coli alanyl-tRNA synthetase to a cognate RNA minihelix involves a transition state sensitive to changes in the tRNA acceptor stem [7].
• The invariant arginine in motif 2 of Escherichia coli alanyl-tRNA synthetase is important for catalysis but not for substrate binding [8].
• Lysine73, located in the adenylate synthesis domain of Escherichia coli alanyl-tRNA synthetase (AlaRS), was previously indicated to be an important residue for the interaction of this enzyme with the acceptor stem of its cognate tRNA (tRNA(Ala)) [9].
• Synthesis of an mRNA fragment of alanyl-tRNA synthetase gene in Escherichia coli using the 6-methyl-3-pyridyl group for protection of the imide functions of uridine and guanosine [10].

Biological context of ECs3554

• Site-directed random mutagenesis has been employed to generate a set of proteins containing amino acid substitutions in a portion of motif 2 of AlaRS [8].
• It was previously shown that recognition by AlaRS is severely affected by a simple base pair transversion of the G2:C71 pair at the second position in the RNA helix [11].
• Kinetic parameters of tRNA aminoacylation by Escherichia coli AlaRS obtained by the new method are in excellent agreement with those measured by the conventional method [12].
• Alanyl-tRNA synthetase (AlaRS) from Escherichia coli is a multimeric enzyme that catalyzes the esterification of alanine to tRNA(Ala) in the ATP-dependent aminoacylation reaction [13].
• The relative genetic position of the following four mutations of ribosomal protein S5 has been determined: spc-13, a mutation to spectinomycin resistance; stri N421 and strid1023, mutations suppressing dependence on streptomycin and sup0-1, a mutation suppressing partially the temperature-sensitive phenotype of an alanyl-tRNA synthetase mutation [14].

Anatomical context of ECs3554

• The function of SmpB protein in the trans-translation system was evaluated using the well-defined cell-free translation system consisting of purified ribosome, alanyl-tRNA synthetase and elongation factors [15].

Associations of ECs3554 with chemical compounds

• A cysteine in the C-terminal region of alanyl-tRNA synthetase is important for aminoacylation activity [13].
• In the case of mild DTNB treatment, only two of the six cysteines in AlaRS are modified, with release of all zinc and partial loss of aminoacylation activity [13].
• The assay is based on coupling the alanyl-tRNA synthetase-dependent formation of AMP to the lactate dehydrogenase oxidation of NADH [16].
• Furthermore, urea denaturation experiments demonstrate the role of zinc in stabilization of AlaRS structure [17].
• Replacement of this residue with glutamine produced a reduction in the catalytic efficiency of AlaRS in the aminoacylation assay, primarily through an increase in the apparent KM for tRNA(Ala) [Hill, K., and Schimmel, P. (1989) Biochemistry 28, 2577-2586] [9].

Other interactions of ECs3554

• Analysis of the different mutants revealed (or confirmed for some nucleotides) their role as positive and/or negative determinants in AlaRS, LysRS, and ArgRS recognition [18].
• Here it is shown that HisRS and TrpRS (Bacillus stearothermophilus) and AlaRS (E. coli) also synthesize the hybrid compounds Ap4G, Ap4C, and Ap4U [19].

Analytical, diagnostic and therapeutic context of ECs3554

• Northern blot analysis indicated that the mRNA for alanyl-tRNA synthetase is 3.8 kilobase pairs in mRNA isolated from posterior silk gland, middle silk gland, and ovarian tissue [20].

References