Crystal structure of quinohemoprotein amine dehydrogenase from Pseudomonas putida. Identification of a novel quinone cofactor encaged by multiple thioether cross-bridges.
The crystal structure of a quinohemoprotein amine dehydrogenase from Pseudomonas putida has been determined at 1.9-A resolution. The enzyme comprises three non-identical subunits: a four-domain alpha-subunit that harbors a di-heme cytochrome c, a seven-bladed beta-propeller beta-subunit that provides part of the active site, and a small gamma-subunit that contains a novel cross-linked, proteinous quinone cofactor, cysteine tryptophylquinone. More surprisingly, the catalytic gamma-subunit contains three additional chemical cross-links that encage the cysteine tryptophylquinone cofactor, involving a cysteine side chain bridged to either an Asp or Glu residue all in a hitherto unknown thioether bonding with a methylene carbon atom of acidic amino acid side chains. Thus, the structure of the 79-residue gamma-subunit is quite unusual, containing four internal cross-links in such a short polypeptide chain that would otherwise be difficult to fold into a globular structure.
Satoh
Atsuko
A
Department of Chemistry, Graduate School of Science, Osaka City University, Osaka 558-8585, Japan.
Kim
Jong-Keun
JK
Miyahara
Ikuko
I
Devreese
Bart
B
Vandenberghe
Isabel
I
Hacisalihoglu
Ayse
A
Okajima
Toshihide
T
Kuroda
Shun'ichi
S
Adachi
Osao
O
Duine
Johannis A
JA
Van Beeumen
Jozef
J
Tanizawa
Katsuyuki
K
Hirotsu
Ken
K
D000596:Amino Acids / Q000737:chemistry; D001224:Aspartic Acid / Q000737:chemistry; D001665:Binding Sites; D020134:Catalytic Domain; D018360:Crystallography, X-Ray; D003545:Cysteine / Q000737:chemistry; D004151:Dipeptides / Q000096:biosynthesis / Q000737:chemistry*; D018698:Glutamic Acid / Q000737:chemistry; D045563:Indolequinones; D008958:Models, Molecular; D000587:Oxidoreductases Acting on CH-NH Group Donors / Q000737:chemistry*; D011487:Protein Conformation; D017510:Protein Folding; D017434:Protein Structure, Tertiary; D016958:Pseudomonas putida / Q000201:enzymology*; D011809:Quinones / Q000737:chemistry*; D013440:Sulfides / Q000737:chemistry
D000596:Amino Acids; D004151:Dipeptides; D045563:Indolequinones; D011809:Quinones; D013440:Sulfides; C447619:cysteine tryptophylquinone; D001224:Aspartic Acid; D018698:Glutamic Acid; D000587:Oxidoreductases Acting on CH-NH Group Donors; C119497:quinohemoprotein amine dehydrogenase; D003545:Cysteine