Metal induced structural changes observed in hexameric insulin.
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.
Sreekanth
R
R
Centre of Advanced Study in Crystallography and Biophysics, University of Madras, Chennai, India.
Pattabhi
Vasantha
V
Rajan
S S
SS
D003460:Crystallization; D006801:Humans; D007328:Insulin / Q000737:chemistry*; D008670:Metals / Q000737:chemistry*; D008958:Models, Molecular; D011487:Protein Conformation
D007328:Insulin; D008670:Metals