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A cytosolic Ni(II) sensor in cyanobacterium: Nickel-detection follows nickel-affinity across four families of metal-sensors

Foster, AW; Patterson, CJ; Pernil, R; Hess, CR; Robinson, NJ

A cytosolic Ni(II) sensor in cyanobacterium: Nickel-detection follows nickel-affinity across four families of metal-sensors Thumbnail


Authors

AW Foster

CJ Patterson

R Pernil

CR Hess



Abstract

Efflux of surplus Ni(II) across the outer and inner membranes of Synechocystis PCC 6803 is mediated by the Nrs system under the control of a sensor of periplasmic Ni(II), NrsS. Here, we show that the product of ORF sll0176, which encodes a CsoR/RcnR-like protein now designated InrS (for internal nickel-responsive sensor), represses nrsD (NrsD is deduced to efflux Ni(II) across the inner membrane) from a cryptic promoter between the final two ORFs in the nrs operon. Transcripts initiated from the newly identified nrsD promoter accumulate in response to nickel or cobalt but not copper, and recombinant InrS forms specific, Ni(II)-inhibited complexes with the nrsD promoter region. Metal-dependent difference spectra of Ni(II)- and Cu(I)-InrS are similar to Cu(I)-sensing CsoR and dissimilar to Ni(II)/Co(II)-sensing RcnR, consistent with factors beyond the primary coordination sphere switching metal selectivity. Competition with chelators mag-fura-2, nitrilotriacetic acid, EDTA, and EGTA estimate KD Ni(II) for the tightest site of InrS as 2.05 (±1.5) × 10−14 m, and weaker KD Ni(II) for the cells' metal sensors of other types: Zn(II) co-repressor Zur, Co(II) activator CoaR, and Zn(II) derepressor ZiaR. Ni(II) transfer to InrS occurs upon addition to Ni(II) forms of each other sensor. InrS binds Ni(II) sufficiently tightly to derepress Ni(II) export at concentrations below KD Ni(II) of the other sensors.

Citation

Foster, A., Patterson, C., Pernil, R., Hess, C., & Robinson, N. (2012). A cytosolic Ni(II) sensor in cyanobacterium: Nickel-detection follows nickel-affinity across four families of metal-sensors. Journal of Biological Chemistry, 287(15), 12142-12151. https://doi.org/10.1074/jbc.m111.338301

Journal Article Type Article
Publication Date Apr 1, 2012
Deposit Date Apr 2, 2012
Publicly Available Date Mar 29, 2024
Journal Journal of Biological Chemistry
Print ISSN 0021-9258
Electronic ISSN 1083-351X
Publisher American Society for Biochemistry and Molecular Biology
Peer Reviewed Peer Reviewed
Volume 287
Issue 15
Pages 12142-12151
DOI https://doi.org/10.1074/jbc.m111.338301
Keywords Hydrogenase, Metal Homeostasis, Metalloproteins, Metals, Nickel, ArsR/SmtB Family, CsoR/RcnR Family, Fur Family, MerR Family, Metal Specificity.

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Full-text available under a Creative Commons Attribution Non-Commercial License.





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