7956 x 6784 px | 67,4 x 57,4 cm | 26,5 x 22,6 inches | 300dpi
Date de la prise de vue:
2007
Informations supplémentaires:
Heme Porphyrin Ring The iron atom in heme binds to the 4 nitrogen atoms in the centre of the porphyrin ring The heme group is located in a crevice in the myoglobin molecule A heme group consists of an iron (Fe) ion (charged atom) held in a heterocyclic ring, known as a porphyrin. The iron ion, which is the site of oxygen binding, coordinates with the four nitrogens in the center of the ring, which all lie in one plane. A sixth position can reversibly bind oxygen, completing the octahedral group of six ligands. Oxygen binds in an "end-on bent" geometry where one oxygen atom binds Fe and the other protrudes at an angle. When oxygen is not bound, a very weakly bonded water molecule fills the site, forming a distorted octahedron.
