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Title: Structure and specificity of a permissive bacterial C-prenyltransferase

Authors:
; ; ; ; ; ; ; ; ;
Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States). Advanced Photon Source (APS)
Sponsoring Org.:
NIHOTHER
OSTI Identifier:
1356427
Resource Type:
Journal Article
Resource Relation:
Journal Name: Nature Chemical Biology; Journal Volume: 13; Journal Issue: 4
Country of Publication:
United States
Language:
ENGLISH

Citation Formats

Elshahawi, Sherif I., Cao, Hongnan, Shaaban, Khaled A., Ponomareva, Larissa V., Subramanian, Thangaiah, Farman, Mark L., Spielmann, H. Peter, Phillips, George N., Thorson, Jon S., and Singh, Shanteri. Structure and specificity of a permissive bacterial C-prenyltransferase. United States: N. p., 2017. Web. doi:10.1038/nchembio.2285.
Elshahawi, Sherif I., Cao, Hongnan, Shaaban, Khaled A., Ponomareva, Larissa V., Subramanian, Thangaiah, Farman, Mark L., Spielmann, H. Peter, Phillips, George N., Thorson, Jon S., & Singh, Shanteri. Structure and specificity of a permissive bacterial C-prenyltransferase. United States. doi:10.1038/nchembio.2285.
Elshahawi, Sherif I., Cao, Hongnan, Shaaban, Khaled A., Ponomareva, Larissa V., Subramanian, Thangaiah, Farman, Mark L., Spielmann, H. Peter, Phillips, George N., Thorson, Jon S., and Singh, Shanteri. Mon . "Structure and specificity of a permissive bacterial C-prenyltransferase". United States. doi:10.1038/nchembio.2285.
@article{osti_1356427,
title = {Structure and specificity of a permissive bacterial C-prenyltransferase},
author = {Elshahawi, Sherif I. and Cao, Hongnan and Shaaban, Khaled A. and Ponomareva, Larissa V. and Subramanian, Thangaiah and Farman, Mark L. and Spielmann, H. Peter and Phillips, George N. and Thorson, Jon S. and Singh, Shanteri},
abstractNote = {},
doi = {10.1038/nchembio.2285},
journal = {Nature Chemical Biology},
number = 4,
volume = 13,
place = {United States},
year = {Mon Feb 06 00:00:00 EST 2017},
month = {Mon Feb 06 00:00:00 EST 2017}
}
  • ABSTRACT Cytochromecoxidases are members of the heme-copper oxidase superfamily. These enzymes have different subunits, cofactors, and primary electron acceptors, yet they all contain identical heme-copper (Cu B) binuclear centers within their catalytic subunits. The uptake and delivery pathways of the Cu Batom incorporated into this active site, where oxygen is reduced to water, are not well understood. Our previous work with the facultative phototrophic bacteriumRhodobacter capsulatusindicated that the copper atom needed for the Cu Bsite ofcbb 3-type cytochromecoxidase (cbb 3-Cox) is imported to the cytoplasm by a major facilitator superfamily-type transporter, CcoA. In this study, a comparative genomic analysis ofmore » CcoA orthologs in alphaproteobacterial genomes showed that CcoA is widespread among organisms and frequently co-occurs with cytochromecoxidases. To define the specificity of CcoA activity, we investigated its function inRhodobacter sphaeroides, a close relative ofR. capsulatusthat contains bothcbb 3- andaa 3-Cox. Phenotypic, genetic, and biochemical characterization of mutants lacking CcoA showed that in its absence, or even in the presence of its bypass suppressors, only the production ofcbb 3-Cox and not that ofaa 3-Cox was affected. We therefore concluded that CcoA is dedicated solely tocbb 3-Cox biogenesis, establishing that distinct copper uptake systems provide the Cu Batoms to the catalytic sites of these two similar cytochromecoxidases. These findings illustrate the large variety of strategies that organisms employ to ensure homeostasis and fine control of copper trafficking and delivery to the target cuproproteins under different physiological conditions. IMPORTANCEThecbb 3- andaa 3-type cytochromecoxidases belong to the widespread heme-copper oxidase superfamily. They are membrane-integral cuproproteins that catalyze oxygen reduction to water under hypoxic and normoxic growth conditions. These enzymes diverge in terms of subunit and cofactor composition, yet they all share a conserved heme-copper binuclear site within their catalytic subunit. In this study, we show that the copper atoms of the catalytic center of two similar cytochromecoxidases from this superfamily are provided by different copper uptake systems during their biogenesis. This finding illustrates different strategies by which organisms fine-tune the trafficking of copper, which is an essential but toxic micronutrient.« less
  • Cytochrome c oxidases are members of the heme-copper oxidase superfamily. These enzymes have different subunits, cofactors, and primary electron acceptors, yet they all contain identical heme-copper (Cu B) binuclear centers within their catalytic subunits. The uptake and delivery pathways of the Cu B atom incorporated into this active site, where oxygen is reduced to water, are not well understood. Our previous work with the facultative phototrophic bacterium Rhodobacter capsulatus indicated that the copper atom needed for the Cu B site of cbb 3-type cytochrome c oxidase (cbb 3-Cox) is imported to the cytoplasm by a major facilitator superfamily-type transporter, CcoA.more » In this study, a comparative genomic analysis of CcoA orthologs in alphaproteobacterial genomes showed that CcoA is widespread among organisms and frequently co-occurs with cytochrome c oxidases. To define the specificity of CcoA activity, we investigated its function in Rhodobacter sphaeroides, a close relative of R. capsulatus that contains both cbb 3- and aa 3-Cox. Phenotypic, genetic, and biochemical characterization of mutants lacking CcoA showed that in its absence, or even in the presence of its bypass suppressors, only the production of cbb 3-Cox and not that of aa 3-Cox was affected. We therefore concluded that CcoA is dedicated solely to cbb 3-Cox biogenesis, establishing that distinct copper uptake systems provide the Cu B atoms to the catalytic sites of these two similar cytochrome c oxidases. In conclusion, these findings illustrate the large variety of strategies that organisms employ to ensure homeostasis and fine control of copper trafficking and delivery to the target cuproproteins under different physiological conditions.« less
  • Oxidative protein folding in Gram-negative bacteria results in the formation of disulfide bonds between pairs of cysteine residues. This is a multistep process in which the dithiol-disulfide oxidoreductase enzyme, DsbA, plays a central role. The structure of DsbA comprises an all helical domain of unknown function and a thioredoxin domain, where active site cysteines shuttle between an oxidized, substrate-bound, reduced form and a DsbB-bound form, where DsbB is a membrane protein that reoxidizes DsbA. Most DsbA enzymes interact with a wide variety of reduced substrates and show little specificity. However, a number of DsbA enzymes have now been identified thatmore » have narrow substrate repertoires and appear to interact specifically with a smaller number of substrates. The transient nature of the DsbA-substrate complex has hampered our understanding of the factors that govern the interaction of DsbA enzymes with their substrates. Here we report the crystal structure of a complex between Escherichia coli DsbA and a peptide with a sequence derived from a substrate. The binding site identified in the DsbA-peptide complex was distinct from that observed for DsbB in the DsbA-DsbB complex. The structure revealed details of the DsbA-peptide interaction and suggested a mechanism by which DsbA can simultaneously show broad specificity for substrates yet exhibit specificity for DsbB. This mode of binding was supported by solution nuclear magnetic resonance data as well as functional data, which demonstrated that the substrate specificity of DsbA could be modified via changes at the binding interface identified in the structure of the complex.« less
  • No abstract prepared.