6onp

Publication Abstract from PubMed

Lanthanide (Ln)-dependent methanol dehydrogenases (MDHs) have been recently shown to be widespread in methylotrophic bacteria. Along with the core MDH protein, XoxF, these systems comprise two other proteins, XoxG (a c-type cytochrome) and XoxJ (a periplasmic binding protein of unknown function), about which little is known. Here, we biochemically and structurally characterize these proteins from the methyltroph, Methylobacterium extorquens AM1. In contrast to results obtained via 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 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.

Biochemical and structural characterization of XoxG and XoxJ and their roles in activity of the lanthanide-dependent methanol dehydrogenase, XoxF.,Featherston ER, Rose HR, McBride MJ, Taylor E, Boal AK, Cotruvo J Jr Chembiochem. 2019 Apr 24. doi: 10.1002/cbic.201900184. PMID:31017712^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.