Zinc Fingers and Thiol−Disulfide Oxidoreductase Activities of Chaperone DnaJ

Tang, Wei; Wang, Chih-chen

doi:10.1021/bi0107593

Cited by 35 publications

(50 citation statements)

References 35 publications

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“…This agreed well with the modular character of DnaJ proteins and suggested that the 79 amino acid cysteine-rich domain is also an autonomous folding unit in the full-length protein. The results were also in good agreement with studies using metalfree full-length DnaJ, which demonstrated that even in the absence of any zinc coordination, DnaJ undergoes probably only local structural changes (36). These local changes most likely include the partial unfolding of the zinc binding region, because in the isolated cysteine-rich domain, absence of zinc has been shown to cause the unfolding of the ␤-hairpin structure (21).…”

Section: Discussionsupporting

confidence: 79%

The Roles of the Two Zinc Binding Sites in DnaJ

Linke

Wolfram

Bussemer

et al. 2003

Journal of Biological Chemistry

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All type I DnaJ (Hsp40) homologues share the presence of two highly conserved zinc centers. To elucidate their function, we constructed DnaJ mutants that separately replaced cysteines of either zinc center I or zinc center II with serine residues. We found that in the absence of zinc center I, the autonomous, DnaK-independent chaperone activity of DnaJ is dramatically reduced. Surprisingly, this only slightly impaired the in vivo function of DnaJ, and its ability to function as a co-chaperone in the DnaK/DnaJ/GrpE foldase machine. The DnaJ zinc center II, on the other hand, was found to be absolutely essential for the in vivo and in vitro function of DnaJ. This did not seem to be caused by a lack of substrate binding affinity or an inability to work as an ATPase-stimulating factor. Rather it appears that zinc center II mutant proteins lack a necessary additional interaction site with DnaK, which seems to be crucial for locking-in substrate proteins onto DnaK. These findings led us to a model in which ATP hydrolysis in DnaK is only the first step in converting DnaK into its high affinity binding state. Additional interactions between DnaK and DnaJ are required to make the DnaK/DnaJ/ GrpE foldase machinery catalytically active.

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Section: Discussionsupporting

confidence: 79%

The Roles of the Two Zinc Binding Sites in DnaJ

Linke

Wolfram

Bussemer

et al. 2003

Journal of Biological Chemistry

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“…Zn2 is important for the enzymatic activity of DnaJ (Tang and Wang, 2001), such as reduction of insulin disulfides and protein disulfide formation (e.g., oxidative renaturation of reduced RNase) (de Crouy-Chanel et al, 1995). To analyze the catalytic properties of CYO1, we tried to express full-length CYO1 in E. coli, but it was insoluble under all E. coli growth/detergent conditions we tried.…”

Section: Cyo1 Has Protein Zn-dependent Disulfide Isomerase Activitymentioning

confidence: 99%

“…When these bonds are broken, the free B chain is insoluble and precipitates, increasing absorbance at 650 nm. DnaJ in E. coli catalyzes the DTT-dependent reduction of insulin (de Crouy-Chanel et al, 1995;Tang and Wang, 2001;Shi et al, 2005). We measured the reduction of insulin (130 mM Renaturation of reduced, denatured RNase A, which contains eight sulfhydryl groups, involves the oxidation of its thiol groups followed by rearrangement of the disulfides to the native conformation (with four disulfide bridges) (Anfinsen and Scheraga, 1975).…”

Section: Cyo1 Has Protein Zn-dependent Disulfide Isomerase Activitymentioning

confidence: 99%

“…PDI is a molecular chaperone that catalyzes dithiol/disulfide interchange reactions and promotes protein disulfide formation, isomerization, or reduction, depending on the redox potential and nature of the polypeptide substrate (Holmgren, 1979;Freedman, 1989;Gilbert, 1990). Zn2, one of two C 4 -type zinc finger motifs in DnaJ, is important for this enzymatic activity (Goffin and Georgopoulos, 1998;Tang and Wang, 2001;Shi et al, 2005).…”

Section: Introductionmentioning

confidence: 99%

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Arabidopsis Cotyledon-Specific Chloroplast Biogenesis Factor CYO1 Is a Protein Disulfide Isomerase

et al. 2007

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Chloroplast development in cotyledons differs in a number of ways from that in true leaves, but the cotyledon-specific program of chloroplast biogenesis has not been clarified. The cyo1 mutant in Arabidopsis thaliana has albino cotyledons but normal green true leaves. Chloroplasts develop abnormally in cyo1 mutant plants grown in the light, but etioplasts are normal in mutants grown in the dark. We isolated CYO1 by T-DNA tagging and verified that the mutant allele was responsible for the albino cotyledon phenotype by complementation. CYO1 has a C 4 -type zinc finger domain similar to that of Escherichia coli DnaJ. CYO1 is expressed mainly in young plants under light conditions, and the CYO1 protein localizes to the thylakoid membrane in chloroplasts. Transcription of nuclear photosynthetic genes is generally unaffected by the cyo1 mutation, but the level of photosynthetic proteins is decreased in cyo1 mutants. Recombinant CYO1 accelerates disulfide bond reduction in the model substrate insulin and renatures RNase A, indicating that CYO1 has protein disulfide isomerase activity. These results suggest that CYO1 has a chaperone-like activity required for thylakoid biogenesis in cotyledons.

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“…Moreover, DnaJ has been found to have thiol-disulfide oxidoreductase activity but little, if any, isomerase activity (14).…”

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confidence: 99%

The C-terminal (331–376) Sequence of Escherichia coli DnaJ Is Essential for Dimerization and Chaperone Activity

Shi

Hong

Wang

2005

Journal of Biological Chemistry

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DnaJ, an Escherichia coli Hsp40 protein composed of 376 amino acid residues, is a chaperone with thioldisulfide oxidoreductase activity. We present here for the first time a small angle x-ray scattering study of intact DnaJ and a truncated version, DnaJ (1-330), in solution. The molecular weight of DnaJ and DnaJ (1-330) determined by both small angle x-ray scattering and size-exclusion chromatography provide direct evidence that DnaJ is a homodimer and DnaJ (1-330) is a monomer. The restored models show that DnaJ is a distorted -shaped dimeric molecule with the C terminus of each subunit forming the central part of the , whereas DnaJ (1-330) exists as a monomer. This indicates that the deletion of the C-terminal 46 residues of DnaJ impairs the association sites, although it does not cause significant conformational changes. Biochemical studies reveal that DnaJ (1-330), while fully retaining its thiol-disulfide oxidoreductase activity, is structurally less stable, and its peptide binding capacity is severely impaired relative to that of the intact molecule. Together, our results reveal that the C-terminal (331-376) residues are directly involved in dimerization, and the dimeric structure of DnaJ is necessary for its chaperone activity but not required for the thiol-disulfide oxidoreductase activity.Hsp40 proteins collaborate specifically with Hsp70 proteins and some other factors to participate in a wide range of cellular processes essential to cell survival, such as assisting the folding, assembly, disassembly, and translocation of newly synthesized proteins, by suppressing aggregation or mediating degradation of misfolded proteins (1, 2). The Hsp40 family proteins are divided into three subtypes (3) (see Scheme 1). They all contain a J domain responsible for binding to the ATPase domain and stimulating the ATPase activity of Hsp70. Type I Hsp40 proteins, such as Escherichia coli DnaJ, yeast Yjd1, and human Hdj-2, have a Gly/Phe-rich region, which has been suggested to assist J domain interactions with Hsp70 (4). The Gly/Phe-rich region is followed by a conserved cysteine-rich region forming a zinc finger domain and a poorly conserved C-terminal domain. The peptide binding site(s) has been found to locate within these two domains (5-7). Type II Hsp40 proteins, such as yeast Sis1 and mammalian Hdj-1, also contain the J, a Gly/Phe-rich region, and C-terminal domains but without the zinc finger domain (8, 9). Both type I and type II Hsp40 proteins act as molecular chaperones to bind and deliver nonnative proteins to Hsp70 (7, 8, 10), but they are not functionally equivalent (11). Type III Hsp40 proteins, such as yeast YJL162c and virus T antigen, contain only the J domain, and they do not function as molecular chaperones (3).In addition to the DnaK-dependent co-chaperone activity described above, DnaJ also exerts autonomous DnaK-independent chaperone activity (9, 12, 13), which is characterized by its ability to bind with unfolded proteins and prevent them from irreversible aggregation (10, 11). Moreover, DnaJ has ...

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Zinc Fingers and Thiol−Disulfide Oxidoreductase Activities of Chaperone DnaJ

Cited by 35 publications

References 35 publications

The Roles of the Two Zinc Binding Sites in DnaJ

The Roles of the Two Zinc Binding Sites in DnaJ

Arabidopsis Cotyledon-Specific Chloroplast Biogenesis Factor CYO1 Is a Protein Disulfide Isomerase

The C-terminal (331–376) Sequence of Escherichia coli DnaJ Is Essential for Dimerization and Chaperone Activity

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