1WE1

Crystal structure of heme oxygenase-1 from cyanobacterium Synechocystis sp. PCC6803 in complex with heme

Summary for 1WE1

• Entry DOI: 10.2210/pdb1we1/pdb
• Descriptor: Heme oxygenase 1, PHOSPHATE ION, CHLORIDE ION, ... (6 entities in total)
• Functional Keywords: oxidoreductase
• Biological source: Synechocystis sp.
• Total number of polymer chains: 4
• Total formula weight: 111648.57

Authors

Sugishima, M.,Migita, C.T.,Zhang, X.,Yoshida, T.,Fukuyama, K. (deposition date: 2004-05-21, release date: 2004-12-21, Last modification date: 2023-10-25)

Primary citation

Sugishima, M.,Migita, C.T.,Zhang, X.,Yoshida, T.,Fukuyama, K.
Crystal structure of heme oxygenase-1 from cyanobacterium Synechocystis sp. PCC 6803 in complex with heme
Eur.J.Biochem., 271:4517-4525, 2004

PubMed Abstract: Heme oxygenase (HO) catalyzes the oxidative degradation of heme utilizing molecular oxygen and reducing equivalents. In photosynthetic organisms, HO functions in the biosynthesis of such open-chain tetrapyrroles as phyto-chromobilin and phycobilins, which are involved in the signal transduction for light responses and light harvesting for photosynthesis, respectively. We have determined the first crystal structure of a HO-1 from a photosynthetic organism, Synechocystis sp. PCC 6803 (Syn HO-1), in complex with heme at 2.5 A resolution. Heme-Syn HO-1 shares a common folding with other heme-HOs. Although the heme pocket of heme-Syn HO-1 is, for the most part, similar to that of mammalian HO-1, they differ in such features as the flexibility of the distal helix and hydrophobicity. In addition, 2-propanol derived from the crystallization solution occupied the hydrophobic cavity, which is proposed to be a CO trapping site in rat HO-1 that suppresses product inhibition. Although Syn HO-1 and mammalian HO-1 are similar in overall structure and amino acid sequence (57% similarity vs. human HO-1), their molecular surfaces differ in charge distribution. The surfaces of the heme binding sides are both positively charged, but this patch of Syn HO-1 is narrow compared to that of mammalian HO-1. This feature is suited to the selective binding of ferredoxin, the physiological redox partner of Syn HO-1; the molecular size of ferredoxin is approximately 10 kDa whereas the size of NADPH-cytochrome P450 reductase, a reducing partner of mammalian HO-1, is approximately 77 kDa. A docking model of heme-Syn HO-1 and ferredoxin suggests indirect electron transfer from an iron-sulfur cluster in ferredoxin to the heme iron of heme-Syn HO-1.

PubMed: 15560792
DOI: 10.1111/j.1432-1033.2004.04411.x

Experimental method

X-RAY DIFFRACTION (2.5 Å)