PMID:7592474

Identification and nucleotide sequences of mxaA, mxaC, mxaK, mxaL, and mxaD genes from Methylobacterium extorquens AM1

MxaC was identified through DNA sequencing of a 4.4-kb region containing genes involved in calcium incorporation into methanol dehydrogenase

"The DNA sequence for a 4.4-kb HindIII-XhoI Methylobacterium extorquens AM1 DNA fragment that is known to contain three genes (mxaAKL) involved in incorporation of calcium into methanol dehydrogenase"
Mutant complementation studies showed that mxaC is required for methanol oxidation

"Of the three previously unidentified genes (mxaC, mxaD, and orf1), mutant complementation studies showed that mxaC is required for methanol oxidation"
MxaC is part of the mxaSACKL gene cluster

"A combination of sequence analysis, mutant complementation data, and gene expression studies showed that these genes correspond to mxaSACKLDorf1"

file:METEA/mxaC/mxaC-uniprot.txt

UniProt entry for mxaC membrane protein with vWFA domain

MxaC is 355 amino acids with predicted molecular weight of 37.5 kDa

"355 AA; 37569 MW"
Contains a von Willebrand factor A (VWFA) domain at residues 86-259

"DOMAIN 86..259"
Has two predicted transmembrane helices (residues 51-72 and 307-325)

"TRANSMEM 51..72"
Second predicted transmembrane helix

"TRANSMEM 307..325"
Member of COG2304 family

"eggNOG; COG2304; Bacteria."

file:METEA/mxaC/mxaC-notes.md

Research notes on MxaC function and role in methanol dehydrogenase assembly

MxaC is part of a MoxR/VWA complex with MxaS, MxaL, and MxaR

"likely assemble into a MoxR/VWA complex"
This complex specializes in metal cofactor insertion

"specializes in metal cofactor insertion"
vWFA domains typically mediate protein-protein interactions and metal coordination

"vWFA domains typically mediate protein-protein interactions and metal coordination"
MxaC may serve as a scaffold organizing the assembly machinery at the membrane-periplasm interface

"scaffold that organizes the assembly machinery at the membrane-periplasm interface"

file:METEA/mxaC/mxaC-deep-research-falcon.md

Falcon deep research report: mxaC / MxaC (UniProt C5AQA2) in Methylorubrum extorquens AM1

"von Willebrand factor A (VWA) domain-containing auxiliary protein"
"biogenesis/maturation of the Ca2+-dependent, PQQ-dependent methanol dehydrogenase (MxaFI)"
"rather than catalyzing methanol oxidation directly"
"The best-supported functional role for MxaC is in the **Ca2+ incorporation step**"
"Loss of mxaC yields **inactive MDH** that can be **rescued by Ca2+ treatment**"
"with the assistance of proteins … MxaC … Ca2+ is incorporated into the catalytic center of MxaF"
"in vitro incubation with Ca2+ at pH 9.5 restored** both the characteristic **345 nm absorption** feature and **enzymatic activity**"
"grouped with other VWA proteins (e.g., MxaS, MxaL) and a **MoxR-class AAA+ ATPase (MxaR)**"
"VWA-domain auxiliary factor that likely collaborates with the AAA+ protein **MxaR**"
"auxiliary proteins required for MDH maturation"
"periplasmic PQQ-dependent MDH system"
"MxaC is not described as an electron carrier"
"that MxaC is itself an enzyme catalyzing methanol oxidation"