"XoxG is a **periplasmic, heme c–binding cytochrome** purified from the periplasmic fraction with a **cleaved signal peptide**, and it functions as the **physiological electron acceptor** for lanthanide-dependent XoxF methanol dehydrogenase activity"

"is genomically adjacent to **xoxF1** (META1_1740) and **xoxJ** (META1_1742), forming an **xoxF–xoxG–xoxJ** module"

"The mature N-terminus was identified as **Gln27 after cleavage of the periplasmic signal peptide**"

"The heme is attached via the canonical **CXXCH** motif (Cys95/Cys98)"

"The heme iron is axially ligated by **His99 and Met143**"

"Em = +172 ± 1 mV at pH 7.0"

"This is substantially lower than a cited value for the Ca-dependent partner cytochrome MxaG (**~+256 mV**)"

"loss of **xoxG** yields a growth defect equivalent to loss of both **xoxF1 and xoxF2**, consistent with XoxG being essential for XoxF-dependent methanol oxidation"

"Km for XoxG increased ~3-fold from La to Nd"

"the functional model is that XoxG transfers electrons onward into the respiratory chain"

"XoxG (a c -type cytochrome)"

"using their physiological electron acceptor, XoxG"

"the unusually low reduction potential of XoxG (+172 mV)"

"the K m for XoxG markedly increases from La to Nd"