Biomaterial Database

Nature of the iron-oxygen bond and control of oxygen affinity of the haem by the structure of the globin in haemoglobin. 1982

M F Perutz

Spectroscopic and chemical evidence speak in favour of the iron-oxygen bond being polar. X-ray analysis shows that the oxygen molecule is inclined at an angle of about 115 degrees to the haem plane. Cooperative binding of oxygen by haemoglobin is attributable to an equilibrium between two alternative structures that differ in oxygen affinity by the equivalent of 3-3.5 kcal/mol. The author has proposed that in the low-affinity structure the globin opposes the movement of the iron atom from its pentacoordinated pyramidal geometry in the haem of deoxyhaemoglobin to its hexacoordinated planar geometry in the haem of oxyhaemoglobin, while in the high-affinity structure this restraint is absent. Recent evidence supporting this mechanism is described.

UI	MeSH Term	Description	Entries
D007501	Iron	A metallic element with atomic symbol Fe, atomic number 26, and atomic weight 55.85. It is an essential constituent of HEMOGLOBINS; CYTOCHROMES; and IRON-BINDING PROTEINS. It plays a role in cellular redox reactions and in the transport of OXYGEN.	Iron-56,Iron 56
D008958	Models, Molecular	Models used experimentally or theoretically to study molecular shape, electronic properties, or interactions; includes analogous molecules, computer-generated graphics, and mechanical structures.	Molecular Models,Model, Molecular,Molecular Model
D009211	Myoglobin	A conjugated protein which is the oxygen-transporting pigment of muscle. It is made up of one globin polypeptide chain and one heme group.
D010108	Oxyhemoglobins	A compound formed by the combination of hemoglobin and oxygen. It is a complex in which the oxygen is bound directly to the iron without causing a change from the ferrous to the ferric state.	Oxycobalt Hemoglobin,Oxycobalthemoglobin,Oxyhemoglobin,Hemoglobin, Oxycobalt
D011487	Protein Conformation	The characteristic 3-dimensional shape of a protein, including the secondary, supersecondary (motifs), tertiary (domains) and quaternary structure of the peptide chain. PROTEIN STRUCTURE, QUATERNARY describes the conformation assumed by multimeric proteins (aggregates of more than one polypeptide chain).	Conformation, Protein,Conformations, Protein,Protein Conformations
D005914	Globins	A superfamily of proteins containing the globin fold which is composed of 6-8 alpha helices arranged in a characterstic HEME enclosing structure.	Globin
D006418	Heme	The color-furnishing portion of hemoglobin. It is found free in tissues and as the prosthetic group in many hemeproteins.	Ferroprotoporphyrin,Protoheme,Haem,Heme b,Protoheme IX
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D013329	Structure-Activity Relationship	The relationship between the chemical structure of a compound and its biological or pharmacological activity. Compounds are often classed together because they have structural characteristics in common including shape, size, stereochemical arrangement, and distribution of functional groups.	Relationship, Structure-Activity,Relationships, Structure-Activity,Structure Activity Relationship,Structure-Activity Relationships
D014907	Whales	Large marine mammals of the order CETACEA. In the past, they were commercially valued for whale oil, for their flesh as human food and in ANIMAL FEED and FERTILIZERS, and for baleen. Today, there is a moratorium on most commercial whaling, as all species are either listed as endangered or threatened.	Beaked Whales,Berardius,Caperea,Dwarf Sperm Whale,Giant Bottle-Nosed Whales,Goose-Beaked Whale,Gray Whale,Mesoplodon,Narwhals,Pygmy Right Whale,Pygmy Sperm Whale,Right Whale, North Atlantic,Right Whale, Southern,Ziphiidae,Ziphius,Eschrichtius robustus,Eubalaena australis,Grey Whale,Monodon monoceros,North Atlantic Right Whale,Beaked Whale,Bottle-Nosed Whale, Giant,Bottle-Nosed Whales, Giant,Dwarf Sperm Whales,Giant Bottle Nosed Whales,Giant Bottle-Nosed Whale,Goose Beaked Whale,Goose-Beaked Whales,Gray Whales,Grey Whales,Narwhal,Pygmy Right Whales,Pygmy Sperm Whales,Right Whale, Pygmy,Right Whales, Pygmy,Right Whales, Southern,Southern Right Whale,Southern Right Whales,Sperm Whale, Dwarf,Sperm Whale, Pygmy,Sperm Whales, Dwarf,Sperm Whales, Pygmy,Whale,Whale, Grey,Whale, Southern Right,Whales, Grey,Whales, Southern Right