Biochemical and Structural Characterization of XoxG and XoxJ and Their Roles in Lanthanide‐Dependent Methanol Dehydrogenase Activity
| Autor: | Emily R. Featherston, Molly J. McBride, Ellison M. Taylor, Amie K. Boal, Hannah R. Rose, Joseph A. Cotruvo |
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| Rok vydání: | 2019 |
| Předmět: |
Cytochrome
Stereochemistry Rhodothermus Cytochrome c Group Saccharomyces cerevisiae 010402 general chemistry Lanthanoid Series Elements 01 natural sciences Biochemistry Redox Article Bacterial Proteins Methylobacterium extorquens Molecular Biology Enzyme Assays biology Methanol dehydrogenase 010405 organic chemistry Chemistry Methanol Cytochrome c Binding protein Organic Chemistry Periplasmic space biology.organism_classification Electron transport chain 0104 chemical sciences Alcohol Oxidoreductases Kinetics Periplasmic Binding Proteins biology.protein Molecular Medicine Oxidation-Reduction |
| Zdroj: | Chembiochem |
| ISSN: | 1439-7633 1439-4227 |
| DOI: | 10.1002/cbic.201900184 |
| Popis: | Lanthanide (Ln)-dependent methanol dehydrogenases (MDHs) have recently been shown to be widespread in methylotrophic bacteria. Along with the core MDH protein, XoxF, these systems contain two other proteins, XoxG (a c-type cytochrome) and XoxJ (a periplasmic binding protein of unknown function), about which little is known. In this work, we have biochemically and structurally characterized these proteins from the methyltroph Methylobacterium extorquens AM1. In contrast to results obtained in an artificial assay system, assays of XoxFs metallated with LaIII , CeIII , and NdIII using their physiological electron acceptor, XoxG, display Ln-independent activities, but the Km for XoxG markedly increases from La to Nd. This result suggests that XoxG's redox properties are tuned specifically for lighter Lns in XoxF, an interpretation supported by the unusually low reduction potential of XoxG (+172 mV). The X-ray crystal structure of XoxG provides a structural basis for this reduction potential and insight into the XoxG-XoxF interaction. Finally, the X-ray crystal structure of XoxJ reveals a large hydrophobic cleft and suggests a role in the activation of XoxF. These studies enrich our understanding of the underlying chemical principles that enable the activity of XoxF with multiple lanthanides in vitro and in vivo. |
| Databáze: | OpenAIRE |
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