Crystal structure of NADH-cytochrome b5 reductase from pig liver at 2.4 A resolution.
The three-dimensional structure of NADH-cytochrome b5 reductase from pig liver microsomes has been determined at 2.4 A resolution by X-ray crystallography. The molecular structure reveals two domains, the FAD binding domain and the NADH domain. A large cleft lies between these two domains and contains the binding site for the FAD prosthetic group. The backbone structure of the FAD binding domain has a great similarity to that of ferredoxin-NADP+ reductase [Karplus, P. A., Daniels, M. J., & Herriott, J. R. (1991) Science 251, 60-65], in spite of the relatively low sequence homology (about 15%) between the two enzymes. On the other hand, the structure of the NADH domain has several structural differences from that of the NADP+ domain of ferredoxin-NADP+ reductase. The size of the cleft between the two domains is larger in NADH-cytochrome b5 reductase than in ferredoxin-NADP+ reductase, which may be responsible for the observed difference in the nucleotide accessibility in the two enzymes.
Nishida
H
H
Research Laboratory of Resources Utilization, Tokyo Institute of Technology, Yokohama, Japan.
Inaka
K
K
Yamanaka
M
M
Kaida
S
S
Kobayashi
K
K
Miki
K
K
D000818:Animals; D001665:Binding Sites; D018360:Crystallography, X-Ray; D003579:Cytochrome Reductases / Q000737:chemistry* / Q000378:metabolism; D042966:Cytochrome-B(5) Reductase; D005287:Ferredoxin-NADP Reductase / Q000737:chemistry / Q000378:metabolism; D005182:Flavin-Adenine Dinucleotide / Q000737:chemistry / Q000378:metabolism; D007700:Kinetics; D008862:Microsomes, Liver / Q000201:enzymology*; D008958:Models, Molecular; D015394:Molecular Structure; D009243:NAD / Q000737:chemistry / Q000378:metabolism; D011487:Protein Conformation; D013552:Swine
D009243:NAD; D005182:Flavin-Adenine Dinucleotide; D005287:Ferredoxin-NADP Reductase; D003579:Cytochrome Reductases; D042966:Cytochrome-B(5) Reductase