Zinc is required for structural stability of the C‐terminus of archaeal translation initiation factor aIF2β

Gutiérrez, Pablo; Coillet-Matillon, S.; Arrowsmith, C.H.; Gehring, Kalle

doi:10.1016/s0014-5793(02)02610-8

Cited by 9 publications

(8 citation statements)

References 26 publications

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“…Although this loop includes bC107 and bC110 of the C2-C2 zinc-binding motif, the tetrahedral coordination to the zinc ion is retained in the present conformation (Fig. 4A), which is consistent with the essentiality of the zinc ion in the stability of aIF2␤ (18). ZBD in the complex is packed closely to HTH, and an interdomain hydrogen bond is discernible between the conserved bT115 in ZBD and bR58 in HTH, in contrast to the uncomplexed form, which shows no obvious interaction between the domains.…”

Section: Resultssupporting

confidence: 79%

Structure of archaeal translational initiation factor 2 βγ–GDP reveals significant conformational change of the β-subunit and switch 1 region

Sokabe

Yao

Sakai

et al. 2006

Proc. Natl. Acad. Sci. U.S.A.

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Archaeal͞eukaryotic initiation factor 2 (a͞eIF2) consists of ␣-, ␤-, and ␥-subunits and delivers initiator methionine tRNA (Met-tRNAi) to a small ribosomal subunit in a GTP-dependent manner. The structures of the aIF2␤␥ (archaeal initiation factor 2 ␤␥) heterodimeric complex in the apo and GDP forms were analyzed at 2.8-and 3.4-Å resolution, respectively. The results showed that the N-terminal helix and the central helix-turn-helix domain of the ␤-subunit bind to the G domain of the ␥-subunit but are distant from domains 2 and 3, to which the ␣-subunit and Met-tRNAi bind. This result is consistent with most of the previous analyses of eukaryotic factors, and thus indicates that the binding mode is essentially conserved among a͞eIF2. Comparison with the uncomplexed structure showed significant differences between the two forms of the ␤-subunit, particularly the C-terminal zinc-binding domain, which does not interact with the ␥-subunit and was suggested previously to be involved in GTP hydrolysis. Furthermore, the switch 1 region in the ␥-subunit, which is shown to be responsible for Met-tRNA i binding by mutational analysis, is moved away from the nucleotide through the interaction with highly conserved R87 in the ␤-subunit. These results implicate that conformational change of the ␤-subunit facilitates GTP hydrolysis by inducing the conformational change of the switch 1 region toward the off state.initiator methionine tRNA ͉ ribosome

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Section: Resultssupporting

confidence: 79%

Structure of archaeal translational initiation factor 2 βγ–GDP reveals significant conformational change of the β-subunit and switch 1 region

Sokabe

Yao

Sakai

et al. 2006

Proc. Natl. Acad. Sci. U.S.A.

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“…The zinc‐finger domain (residues 99–135) is composed of three antiparallel β‐strands (β5, β6, and β7) encompasing residues 112–116, 120–124, and 128–130, respectively. Zinc is required for the structural stability of this domain (Gutierrez et al 2002), and is coordinated by four cysteines at positions 102, 105, 123, and 126. Helix α4, links the core domain and the zinc finger.…”

Section: Resultsmentioning

confidence: 99%

“…Helix α4, links the core domain and the zinc finger. The absence of significant chemical shift changes in the core domain upon folding of the C terminus (Cho and Hoffman 2002; Gutierrez et al 2002), the lack of NOEs between the two domains and their different RDC alignment tensors suggest that there are minimal interactions between the core domain and the zinc finger. Superposition of the core and zinc finger domains of Mj_aIF2β to Mt_aIF2β gives backbone RSMDs of 2.24 Å.…”

Section: Resultsmentioning

confidence: 99%

Structure of the archaeal translation initiation factor aIF2β from Methanobacterium thermoautotrophicum: Implications for translation initiation

et al. 2004

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AbstractaIF2␤ is the archaeal homolog of eIF2␤, a member of the eIF2 heterotrimeric complex, implicated in the delivery of Met-tRNA i Met to the 40S ribosomal subunit. We have determined the solution structure of the intact ␤-subunit of aIF2 from Methanobacterium thermoautotrophicum. aIF2␤ is composed of an unfolded N terminus, a mixed ␣/␤ core domain and a C-terminal zinc finger. NMR data shows the two folded domains display restricted mobility with respect to each other. Analysis of the aIF2␥ structure docked to tRNA allowed the identification of a putative binding site for the ␤-subunit in the ternary translation complex. Based on structural similarity and biochemical data, a role for the different secondary structure elements is suggested.

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“…First, it is reasonable that the two proteins (ribosome-binding factor A [spot 24] and GTPbinding translation factor [spot 427]) were derepressed in the ⌬310 mutant. Several studies have indicated that zinc is required for the structural stability of translation initiation fac- (22,35). It is possible that ribosome-binding factors compete with a translation initiation factor for the resources of ribosomes (19,21).…”

Section: Discussionmentioning

confidence: 99%

Functional Definition and Global Regulation of Zur, a Zinc Uptake Regulator in a Streptococcus suis Serotype 2 Strain Causing Streptococcal Toxic Shock Syndrome

Feng

Zhang

et al. 2008

J Bacteriol

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Zinc is an essential trace element for all living organisms and plays pivotal roles in various cellular processes. However, an excess of zinc is extremely deleterious to cells. Bacteria have evolved complex machineries (such as efflux/influx systems) to control the concentration at levels appropriate for the maintenance of zinc homeostasis in cells and adaptation to the environment. The Zur (zinc uptake regulator) protein is one of these functional members involved in the precise control of zinc homeostasis. Here we identified a zur homologue designated 310 from Streptococcus suis serotype 2, strain 05ZYH33, a highly invasive isolate causing streptococcal toxic shock syndrome. Biochemical analysis revealed that the protein product of gene 310 exists as a dimer form and carries zinc ions. An isogenic gene replacement mutant of gene 310, the ⌬310 mutant, was obtained by homologous recombination. Physiological tests demonstrated that the ⌬310 mutant is specifically sensitive to Zn 2؉ , while functional complementation of the ⌬310 mutant can restore its duration capability, suggesting that 310 is a functional member of the Zur family. Two-dimensional electrophoresis indicated that nine proteins in the ⌬310 mutant are overexpressed in comparison with those in the wild type. DNA microarray analyses suggested that 121 genes in the ⌬310 mutant are affected, of which 72 genes are upregulated and 49 are downregulated. The transcriptome of S. suis serotype 2 with high Zn 2؉ concentrations also showed 117 differentially expressed genes, with 71 upregulated and 46 downregulated. Surprisingly, more than 70% of the genes differentially expressed in the ⌬310 mutant were the same as those in S. suis serotype 2 that were differentially expressed in response to high Zn 2؉ concentration, consistent with the notion that 310 is involved in zinc homeostasis. We thus report for the first time a novel zinc-responsive regulator, Zur, from Streptococcus suis serotype 2.Streptococcus suis 2 is a gram-positive pathogenic bacterium capable of infecting both piglets and humans and causing serious diseases such as arthritis, meningitis, and septicemia (58). It has spread to nearly 20 countries, resulting in more than 400 human cases of severe infection worldwide (38). In particular, two recent outbreaks (in 1998 and 2005) of severe human S. suis serotype 2 infections in China were characterized by streptococcal toxic shock syndrome, implying that highly invasive variants of S. suis serotype 2 might be emerging in Asia (63,72). Virulence factors related to the pathogenesis of S. suis serotype 2 have been partially elucidated and include capsular polysaccharide (56), suilysin (37), muraminidase-released protein (42), and extracellular factor (59). Very recently, our group (8) reported the whole genome sequences of two virulent S. suis serotype 2 isolates (05ZYH33 and 98HAH12).Similar to other transition metals such as iron, manganese,

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Zinc is required for structural stability of the C‐terminus of archaeal translation initiation factor aIF2β

Cited by 9 publications

References 26 publications

Structure of archaeal translational initiation factor 2 βγ–GDP reveals significant conformational change of the β-subunit and switch 1 region

Structure of archaeal translational initiation factor 2 βγ–GDP reveals significant conformational change of the β-subunit and switch 1 region

Structure of the archaeal translation initiation factor aIF2β from Methanobacterium thermoautotrophicum: Implications for translation initiation

Functional Definition and Global Regulation of Zur, a Zinc Uptake Regulator in a Streptococcus suis Serotype 2 Strain Causing Streptococcal Toxic Shock Syndrome

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