Dataset Information

Transformations of the FeS Clusters of the Methylthiotransferases MiaB and RimO, Detected by Direct Electrochemistry.

ABSTRACT: The methylthiotransferases (MTTases) represent a subfamily of the S-adenosylmethionine (AdoMet) radical superfamily of enzymes that catalyze the attachment of a methylthioether (-SCH3) moiety on unactivated carbon centers. These enzymes contain two [4Fe-4S] clusters, one of which participates in the reductive fragmentation of AdoMet to generate a 5'-deoxyadenosyl 5'-radical and the other of which, termed the auxiliary cluster, is believed to play a central role in constructing the methylthio group and attaching it to the substrate. Because the redox properties of the bound cofactors within the AdoMet radical superfamily are so poorly understood, we have examined two MTTases in parallel, MiaB and RimO, using protein electrochemistry. We resolve the redox potentials of each [4Fe-4S] cluster, show that the auxiliary cluster has a potential higher than that of the AdoMet-binding cluster, and demonstrate that upon incubation of either enzyme with AdoMet, a unique low-potential state of the enzyme emerges. Our results are consistent with a mechanism whereby the auxiliary cluster is transiently methylated during substrate methylthiolation.

SUBMITTER: Maiocco SJ

PROVIDER: S-EPMC5461913 | biostudies-literature | 2016 Oct

REPOSITORIES: biostudies-literature

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Transformations of the FeS Clusters of the Methylthiotransferases MiaB and RimO, Detected by Direct Electrochemistry.

Maiocco Stephanie J SJ Arcinas Arthur J AJ Landgraf Bradley J BJ Lee Kyung-Hoon KH Booker Squire J SJ Elliott Sean J SJ

Biochemistry 20160922 39

The methylthiotransferases (MTTases) represent a subfamily of the S-adenosylmethionine (AdoMet) radical superfamily of enzymes that catalyze the attachment of a methylthioether (-SCH<sub>3</sub>) moiety on unactivated carbon centers. These enzymes contain two [4Fe-4S] clusters, one of which participates in the reductive fragmentation of AdoMet to generate a 5'-deoxyadenosyl 5'-radical and the other of which, termed the auxiliary cluster, is believed to play a central role in constructing the met ...[more]

PMID: 27598886

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Project description:Nanoscale conductive filaments, usually associated with resistive memory or memristor technology, may also be used for chemical sensing and nanophotonic applications; however, realistic implementation of the technology requires precise knowledge of the conditions that control the formation and dissolution of filaments. Here we describe and characterize an addressable direct-write nanoelectrochemical approach to achieve repeatable formation/dissolution of Ag filaments across a ∼100 nm poly(ethylene oxide) (PEO) film containing either Ag+ alone or Ag+ together with 50 nm Ag-nanoparticles acting as bipolar electrodes. Using a conductive AFM tip, formation occurs when the PEO film is subjected to a forward bias, and dissolution occurs under reverse bias. Formation-dissolution kinetics were studied for three film compositions: Ag|PEO-Ag+, Ag|poly(ethylene glycol) monolayer-PEO-Ag+, and Ag|poly(ethylene glycol) monolayer-PEO-Ag+/Ag-nanoparticle. Statistical analysis shows that the distribution of formation times exhibits Gaussian behavior, and the fastest average initial formation time occurs for the Ag|PEO-Ag+ system. In contrast, formation in the presence of Ag nanoparticles likely proceeds by a noncontact bipolar electrochemical mechanism, exhibiting the slowest initial filament formation. Dissolution times are log-normal for all three systems, and repeated reformation of filaments from previously formed structures is characterized by rapid regrowth. The direct-write bipolar electrochemical deposition/dissolution strategy developed here presents an approach to reconfigurable, noncontact in situ wiring of nanoparticle arrays-thereby enabling applications where actively controlled connectivity of nanoparticle arrays is used to manipulate nanoelectronic and nanophotonic behavior. The system further allows for facile manipulation of experimental conditions while simultaneously characterizing surface conditions and filament formation/dissolution kinetics.

Dataset Information

Transformations of the FeS Clusters of the Methylthiotransferases MiaB and RimO, Detected by Direct Electrochemistry.

Publications

Transformations of the FeS Clusters of the Methylthiotransferases MiaB and RimO, Detected by Direct Electrochemistry.

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