Structure of human FIH-1 reveals a unique active site pocket and interaction sites for HIF-1 and von Hippel-Lindau.
The master switch of cellular hypoxia responses, hypoxia-inducible factor 1 (HIF-1), is hydroxylated by factor inhibiting HIF-1 (FIH-1) at a conserved asparagine residue under normoxia, which suppresses transcriptional activity of HIF-1 by abrogating its interaction with transcription coactivators. Here we report the crystal structure of human FIH-1 at 2.8-A resolution. The structural core of FIH-1 consists of a jellyroll-like beta-barrel containing the conserved ferrous-binding triad residues, confirming that FIH-1 is a member of the 2-oxoglutarate-dependent dioxygenase family. Except for the core structure and triad residues, FIH-1 has many structural deviations from other family members including N- and C-terminal insertions and various deletions in the middle of the structure. The ferrous-binding triad region is highly exposed to the solvent, which is connected to a prominent groove that may bind to a helix near the hydroxylation site of HIF-1. The structure, which is in a dimeric state, also reveals the putative von Hippel-Lindau-binding site that is distinctive to the putative HIF-1-binding site, supporting the formation of the ternary complex by FIH-1, HIF-1, and von Hippel-Lindau. The unique environment of the active site and cofactor-binding region revealed in the structure should allow design of selective drugs that can be used in ischemic diseases to promote hypoxia responses.
Lee
Cheolju
C
Center for Cellular Switch Protein Structure, Korea Research Institute of Bioscience and Biotechnology, 52 Euh-eun-dong, Yuseong-gu, Daejeon 305-806, Korea.
Kim
Seung Jun
SJ
Jeong
Dae Gwin
DG
Lee
Soon Mi
SM
Ryu
Seong Eon
SE
D000595:Amino Acid Sequence; D001665:Binding Sites; D003001:Cloning, Molecular; D018360:Crystallography, X-Ray; D018076:DNA, Complementary / Q000378:metabolism; D019281:Dimerization; D015723:Gene Library; D006801:Humans; D006900:Hydroxylation; D000860:Hypoxia; D007656:Ketoglutaric Acids / Q000378:metabolism; D008025:Ligases / Q000737:chemistry* / Q000378:metabolism*; D006899:Mixed Function Oxygenases / Q000378:metabolism; D008954:Models, Biological; D008958:Models, Molecular; D008969:Molecular Sequence Data; D011485:Protein Binding; D011487:Protein Conformation; D017510:Protein Folding; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D012097:Repressor Proteins / Q000737:chemistry* / Q000378:metabolism*; D014157:Transcription Factors / Q000737:chemistry* / Q000378:metabolism*; D025521:Tumor Suppressor Proteins; D044767:Ubiquitin-Protein Ligases; D051794:Von Hippel-Lindau Tumor Suppressor Protein
D018076:DNA, Complementary; D007656:Ketoglutaric Acids; D012097:Repressor Proteins; D014157:Transcription Factors; D025521:Tumor Suppressor Proteins; D006899:Mixed Function Oxygenases; C439790:HIF1AN protein, human; C066046:clavaminate synthase; D044767:Ubiquitin-Protein Ligases; D051794:Von Hippel-Lindau Tumor Suppressor Protein; D008025:Ligases; C497446:VHL protein, human