Three-dimensional structure of the quinoprotein methylamine dehydrogenase from Paracoccus denitrificans determined by molecular replacement at 2.8 A resolution.
The three-dimensional structure of the quinoprotein methylamine dehydrogenase from Paracoccus dentrificans (PD-MADH) has been determined at 2.8 A resolution by the molecular replacement method combined with map averaging procedures, using data collected from an area detector. The structure of methylamine dehydrogenase from Thio-bacillus versutus, which contains an "X-ray" sequence, was used as the starting search model. MADH consists of 2 heavy (H) and 2 light (L) subunits related by a molecular 2-fold axis. The H subunit is folded into seven four-stranded beta segments, forming a disk-shaped structure, arranged with pseudo-7-fold symmetry. A 31-residue elongated tail exists at the N-terminus of the H subunit in MADH from T. versutus but is partially digested in this crystal form of MADH from P. denitrificans, leaving the H subunit about 18 residues shorter. Each L subunit contains 127 residues arranged into 10 beta-strands connected by turns. The active site of the enzyme is located in the L subunit and is accessible via a hydrophobic channel between the H and L subunits. The redox cofactor of MADH, tryptophan tryptophylquinone is highly unusual. It is formed from two covalently linked tryptophan side chains at positions 57 and 107 of the L subunit, one of which contains an orthoquinone.
Chen
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Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, Missouri 63110.
Mathews
F S
FS
Davidson
V L
VL
Huizinga
E G
EG
Vellieux
F M
FM
Hol
W G
WG
D000595:Amino Acid Sequence; D003461:Crystallography; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010084:Oxidation-Reduction; D000587:Oxidoreductases Acting on CH-NH Group Donors / Q000737:chemistry*; D010231:Paracoccus denitrificans / Q000201:enzymology*; D011487:Protein Conformation; D017386:Sequence Homology, Amino Acid
C021567:methylamine dehydrogenase; D000587:Oxidoreductases Acting on CH-NH Group Donors