1JZL
Crystal structure of Sapharca inaequivalvis HbI, I114M mutant ligated to carbon monoxide.
Summary for 1JZL
| Entry DOI | 10.2210/pdb1jzl/pdb |
| Related | 1HBI 1JWN 1JZK 3HBI 3SDH 4SDH |
| Descriptor | GLOBIN I - ARK SHELL, PROTOPORPHYRIN IX CONTAINING FE, CARBON MONOXIDE, ... (4 entities in total) |
| Functional Keywords | invertebrate, hemoglobin, allostery, cooperativity, oxygen-binding, oxygen-transport, heme protein, oxygen storage-transport complex, oxygen storage/transport |
| Biological source | Scapharca inaequivalvis (ark clam) |
| Cellular location | Cytoplasm: P02213 |
| Total number of polymer chains | 2 |
| Total formula weight | 33257.71 |
| Authors | Knapp, J.E.,Gibson, Q.H.,Cushing, L.,Royer Jr., W.E. (deposition date: 2001-09-16, release date: 2001-12-19, Last modification date: 2023-08-16) |
| Primary citation | Knapp, J.E.,Gibson, Q.H.,Cushing, L.,Royer Jr., W.E. Restricting the Ligand-Linked Heme Movement in Scapharca Dimeric Hemoglobin Reveals Tight Coupling between Distal and Proximal Contributions to Cooperativity. Biochemistry, 40:14795-14805, 2001 Cited by PubMed Abstract: Cooperative ligand binding in the dimeric hemoglobin from the blood clam Scapharca inaequivalvis results primarily from tertiary, rather than quaternary, structural changes. Ligand binding is coupled with conformational changes of key residues, including Phe 97, which is extruded from the proximal heme pocket, and the heme group, which moves deeper into the heme pocket. We have tested the role of the heme movement in cooperative function by mutating Ile 114, at the base of the heme pocket. Replacement of this residue with a Met did not disturb the hemoglobin structure or significantly alter equilibrium ligand binding properties. In contrast, substitution with a Phe at position 114 inhibits the ligand-linked movement of the heme group, and substantially reduces oxygen affinity and cooperativity. As the extent of heme movement to the normal position of the ligated state is diminished, Phe 97 is inhibited from its movement into the interface upon ligand binding. These results indicate a tight coupling between these two key cooperative transitions and suggest that the heme movement may be an obligatory trigger for expulsion of Phe 97 from the heme pocket. PubMed: 11732898DOI: 10.1021/bi011071t PDB entries with the same primary citation |
| Experimental method | X-RAY DIFFRACTION (1.5 Å) |
Structure validation
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