In crystallo posttranslational modification within a MauG/pre-methylamine dehydrogenase complex.
MauG is a diheme enzyme responsible for the posttranslational modification of two tryptophan residues to form the tryptophan tryptophylquinone (TTQ) cofactor of methylamine dehydrogenase (MADH). MauG converts preMADH, containing monohydroxylated betaTrp57, to fully functional MADH by catalyzing the insertion of a second oxygen atom into the indole ring and covalently linking betaTrp57 to betaTrp108. We have solved the x-ray crystal structure of MauG complexed with preMADH to 2.1 angstroms. The c-type heme irons and the nascent TTQ site are separated by long distances over which electron transfer must occur to achieve catalysis. In addition, one of the hemes has an atypical His-Tyr axial ligation. The crystalline protein complex is catalytically competent; upon addition of hydrogen peroxide, MauG-dependent TTQ synthesis occurs.
Jensen
Lyndal M R
LM
Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA.
Sanishvili
Ruslan
R
Davidson
Victor L
VL
Wilmot
Carrie M
CM
D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry* / Q000378:metabolism; D055162:Biocatalysis; D020134:Catalytic Domain; D018360:Crystallography, X-Ray; D004792:Enzyme Precursors / Q000737:chemistry* / Q000378:metabolism; D006420:Hemeproteins / Q000737:chemistry* / Q000378:metabolism; D006861:Hydrogen Peroxide / Q000378:metabolism; D045563:Indolequinones / Q000737:chemistry* / Q000378:metabolism; D008024:Ligands; D008958:Models, Molecular; D008969:Molecular Sequence Data; D000587:Oxidoreductases Acting on CH-NH Group Donors / Q000737:chemistry* / Q000378:metabolism; D010231:Paracoccus denitrificans / Q000737:chemistry / Q000201:enzymology / Q000378:metabolism*; D011487:Protein Conformation; D011499:Protein Processing, Post-Translational; D014364:Tryptophan / Q000031:analogs & derivatives* / Q000737:chemistry / Q000378:metabolism
D001426:Bacterial Proteins; D004792:Enzyme Precursors; D006420:Hemeproteins; D045563:Indolequinones; D008024:Ligands; C070569:tryptophan tryptophylquinone; D014364:Tryptophan; D006861:Hydrogen Peroxide; C021567:methylamine dehydrogenase; D000587:Oxidoreductases Acting on CH-NH Group Donors