Primary Citation of Related Structures:   2R34, 2R35, 2R36
PubMed Abstract: 
The metal ions in insulin hexamer play a crucial role in the T to R conformational transitions. We have determined the crystal structures of 2Mn2+, 1Rb1+ and 4Ni2+ human arg-insulin and compared them with the 2Zn2+ structure. The first two structures exist in the T3R3f state like the native 2Zn2+ arg-insulin, while the 4Ni2+ adopts a T6 conformation ...
The metal ions in insulin hexamer play a crucial role in the T to R conformational transitions. We have determined the crystal structures of 2Mn2+, 1Rb1+ and 4Ni2+ human arg-insulin and compared them with the 2Zn2+ structure. The first two structures exist in the T3R3f state like the native 2Zn2+ arg-insulin, while the 4Ni2+ adopts a T6 conformation. The metal coordination is found to be tetrahedral in all the structures except that of nickel where a dual octahedral and tetrahedral coordination is found at one site. Rubidium occupies only one of the high affinity metal binding sites. The metal induced structural changes observed, have been explained.
Related Citations: 
Crystallographic evidence for dual coordination around zinc in the T3R3 human insulin hexamer Ciszak, E., Smith, G.D. (1994) Biochemistry 33: 1512
Organizational Affiliation: 
Centre of Advanced Study in Crystallography and Biophysics, University of Madras, Chennai, India.