ISSN:
0887-3585
Keywords:
amino acid-derived cofactor
;
crystal structure
;
methylamine dehydrogenase
;
molecular replacement
;
oxidoreductase
;
Paracoccus denitrificans
;
pyrroloquinoline quinone
;
quinoprotein
;
tryptophan tryptophylquinone
;
Chemistry
;
Biochemistry and Biotechnology
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Medicine
Notes:
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 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 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 co-valently linked tryptophan side chains at positions 57 and 107 of the L subunit, one of which contains an orthoquinone. © 1992 Wiley-Liss, Inc.
Additional Material:
6 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/prot.340140214
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