Entity
| Entity ID | Chain ID | Description | Type | Chain length | Formula weight | Number of molecules | DB Name (Accession) | Biological source | Descriptive keywords | 
| 1 | A (A) | SULFITE REDUCTASE HEMOPROTEIN | polymer | 497 | 55747.7 | 1 | UniProt (P17846) Pfam (PF03460) Pfam (PF01077) | Escherichia coli | SIRHP | 
| 2 | B (A) | PHOSPHATE ION | non-polymer | 95.0 | 1 | Chemie (PO4) | |||
| 3 | C (A) | POTASSIUM ION | non-polymer | 39.1 | 1 | Chemie (K) | |||
| 4 | D (A) | IRON/SULFUR CLUSTER | non-polymer | 351.6 | 1 | Chemie (SF4) | |||
| 5 | E (A) | SIROHEME | non-polymer | 916.7 | 1 | Chemie (SRM) | |||
| 6 | F (A) | water | water | 18.0 | 486 | Chemie (HOH) | 
Sequence viewer
Contents of the asymmetric unit
| Polymers | Number of chains | 1 | 
| Total formula weight | 55747.7 | |
| Non-Polymers* | Number of molecules | 4 | 
| Total formula weight | 1402.4 | |
| All* | Total formula weight | 57150.1 | 











