Abstract
The three-dimensional structure of the quinoprotein methylamine dehydrogenase from Paracoccus denitrificans (PD-MADH) has been determined at 2.8 Å resolution by the molecular replacement method combined with map averaging procedures, using data collected from an area detector. The structure of methylamine dehydrogenase from Thiobacillus 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 β 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 β-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.
Original language | English |
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Pages (from-to) | 288-299 |
Number of pages | 12 |
Journal | Proteins: Structure function and bioinformatics |
Volume | 14 |
Issue number | 2 |
Publication status | Published - 22 Dec 1992 |
Externally published | Yes |
Keywords
- amino acid-derived cofactor
- crystal structure
- methylamine dehydrogenase
- molecular replacement
- oxidoreductase
- Paracoccus denitrificans
- pyrroloquinoline quinone
- quinoprotein
- tryptophan tryptophylquinone
- methylamine
- tryptophan
- article
- chemical structure
- enzyme active site
- enzyme analysis
- enzyme structure
- nonhuman
- priority journal
- structure analysis