Zinc-dependent protein folding

Cox, Elizabeth H.; McLendon, George

doi:10.1016/s1367-5931(99)00070-8

Cited by 150 publications

(72 citation statements)

References 32 publications

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“…Zinc fingers were initially identified as protein motifs involved in nucleic acid recognition (36), but it is now known that they are also involved in protein-protein interactions (17,22). Our results suggest that a zinc finger formed by C 86 , C 89 , C 103 , and C 106 is involved in dimerization of CVYV P1b and that disturbance of this interaction causes nonspecific aggregation of the protein.…”

Section: Discussionmentioning

confidence: 49%

Protease Activity, Self Interaction, and Small Interfering RNA Binding of the Silencing Suppressor P1b fromCucumber Vein Yellowing Ipomovirus

Vallí

Dujovny

Garcı́a

2008

J Virol

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The RNA silencing pathway mediated by small interfering RNAs (siRNAs) plays an important antiviral role in eukaryotes. To counteract this defense barrier, a large number of plant viruses express proteins with RNA silencing suppression activity. Recently, it was reported that the ipomovirus Cucumber vein yellowing virus (CVYV), which lacks the typical silencing suppressor of members of the family Potyviridae, i.e., HCPro, has a duplicated P1 coding sequence and that the downstream P1 copy, named P1b, has silencing suppression activity. In this study, we provide experimental evidence that P1b is a serine protease that self-cleaves at its C terminus but that its proteolytic activity is not essential for silencing suppression. In contrast, a putative zinc finger and a conserved basic motif in the N-terminal region of the protein are required for efficient silencing suppression. In vitro gel filtration-fast protein liquid chromatography and in vivo bimolecular fluorescence complementation assays showed that P1b binds itself to form oligomeric structures and that the zinc finger-like motif is essential for the self interaction. Moreover, we observed that CVYV P1b forms complexes with synthetic siRNAs, and this ability correlated with both silencing suppression activity and enhancement of Potato virus X pathogenicity in a mutational analysis. Together, these results suggest that CVYV P1b resembles potyviral HCPro and other viral proteins in interfering RNA silencing by preventing siRNA loading into the RNAinduced silencing complex.

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Section: Discussionmentioning

confidence: 49%

Protease Activity, Self Interaction, and Small Interfering RNA Binding of the Silencing Suppressor P1b fromCucumber Vein Yellowing Ipomovirus

Vallí

Dujovny

Garcı́a

2008

J Virol

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“…These surprising results reveal that the presence of a cysteine in the first coordinating position is strictly related to the presence of the zinc ion. Indeed, very few cases are known of proteins with Ͼ35% sequence identity to one another that differ in whether they bind metal with structural role (20)(21)(22)(23)(24)(25). In particular, zinc ion loss occurs rarely and when it does it is generally a result of deletion of the surrounding secondary structure elements and/or loops whose structure the metal stabilizes (20).…”

Section: Discussionmentioning

confidence: 99%

The structural role of the zinc ion can be dispensable in prokaryotic zinc-finger domains

Baglivo

Russo

Esposito

et al. 2009

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

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The recent characterization of the prokaryotic Cys2His2 zinc-finger domain, identified in Ros protein from Agrobacterium tumefaciens, has demonstrated that, although possessing a similar zinc coordination sphere, this domain is structurally very different from its eukaryotic counterpart. A search in the databases has identified Ϸ300 homologues with a high sequence identity to the Ros protein, including the amino acids that form the extensive hydrophobic core in Ros. Surprisingly, the Cys2His2 zinc coordination sphere is generally poorly conserved in the Ros homologues, raising the question of whether the zinc ion is always preserved in these proteins. Here, we present a functional and structural study of a point mutant of Ros protein, Ros56-142C82D, in which the second coordinating cysteine is replaced by an aspartate, 5 previously-uncharacterized representative Ros homologues from Mesorhizobium loti, and 2 mutants of the homologues. Our results indicate that the prokaryotic zinc-finger domain, which in Ros protein tetrahedrally coordinates Zn(II) through the typical Cys2His2 coordination, in Ros homologues can either exploit a CysAspHis2 coordination sphere, previously never described in DNA binding zinc finger domains to our knowledge, or lose the metal, while still preserving the DNA-binding activity. We demonstrate that this class of prokaryotic zinc-finger domains is structurally very adaptable, and surprisingly single mutations can transform a zinc-binding domain into a nonzinc-binding domain and vice versa, without affecting the DNA-binding ability. In light of our findings an evolutionary link between the prokaryotic and eukaryotic zinc-finger domains, based on bacteria-to-eukaryota horizontal gene transfer, is discussed.Cys2His2 zinc finger ͉ DNA binding proteins ͉ metal binding proteins ͉ Ros protein I n eukaryotic organisms the abundant Cys 2 His 2 zinc-finger domain, involved in relevant protein-nucleic acid and proteinprotein interactions, consists of Ͻ30 aa and a zinc ion, tetrahedrally coordinated by 2 histidine nitrogens and 2 cysteine sulfurs and essential for stabilizing the ␤␤␣ fold (1-5). In prokaryotic organisms, the first Cys 2 His 2 zinc-finger domain has been identified only recently in the transcriptional regulator Ros from Agrobacterium tumefaciens (6). The Ros zinc-binding domain contains 2 cysteines occupying the first 2 coordinating positions and 3 histidines (His-92, His-96, and His-97; see Fig. 1). We (7) demonstrated that in the Ros protein the histidines involved in zinc coordination are His-92, acting as the third coordinating residue, and His-97 as the fourth; when His-97 is mutated in Ala, the protein is still able to bind zinc and DNA with His-96 acting as the fourth coordinating residue. The NMR structure of Ros DNA-binding domain ) has shown that the prokaryotic Cys 2 His 2 zinc-finger domain, although having a similar zinc coordination sphere, possesses a novel protein fold, which is very different from that of the eukaryotic counterpart (8). In particular, Ros 56 -142 gl...

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“…The biological functions include electron transfer, dioxygen transport, oxygenation, oxidation, reduction and disproportionation (Walker et al, 1977;Holm et al, 1996). Zinc plays vital roles in biological systems (Cox and McLendon, 2000;Laity et al, 2001;Dudev and Lim, 2003;Lin and Lim, 2004). Zinc plays catalytic and structural roles to maintain the protein configuration.…”

Section: Introductionmentioning

confidence: 99%

Influence of co-solvent on chemical speciation of ternary complexes of bi- and tri- dentate ligands with essential metalions

Kumar

Rao

2013

Chemical Speciation & Bioavailability

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Chemical speciation of ternary complexes of Co(II), Ni(II), Cu(II) and Zn(II) ions with L-aspartic acid and ethylenediamine was studied pH-metrically in the concentration range of 0.0-60.0% v/v acetonitrile-and ethylene glycol-water mixtures maintaining an ionic strength of 0.16 mol L -1 at 303.0 K. Alkalimetric titrations were carried out in different relative concentrations (M:L:X = 1:2.5:2.5, 1:2.5:5.0, 1:5.0:2.5) of metal (M) to aspartic acid (L) to ethylenediamine (X). Stability constants of ternary complexes were calculated and various models were refined with MINIQUAD75. The best fit chemical models were selected based on statistical parameters and residual analysis. The species detected were MLX, ML 2 X, MLX 2 , MLX 2 H and MLX 2 H 2 for Co(II), Ni(II), Cu(II) and Zn(II) in both media. The chemical speciation, metal bioavailability and transportation were explained based on the stability constants.

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Zinc-dependent protein folding

Cited by 150 publications

References 32 publications

Protease Activity, Self Interaction, and Small Interfering RNA Binding of the Silencing Suppressor P1b fromCucumber Vein Yellowing Ipomovirus

Protease Activity, Self Interaction, and Small Interfering RNA Binding of the Silencing Suppressor P1b fromCucumber Vein Yellowing Ipomovirus

The structural role of the zinc ion can be dispensable in prokaryotic zinc-finger domains

Influence of co-solvent on chemical speciation of ternary complexes of bi- and tri- dentate ligands with essential metalions

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