Metal induced conformational changes in human insulin: Crystal structures of Sr2+,Ni2+ and Cu2+ Complexes of human insulin

Crystal structures of sr2+,ni2+ and cu2+ of human insulin complexes have been determined. the structures of sr 2+ and ni2+ complexes are similar to zn2+ insulin and are in t6 conformation. (all the six monomers in the insulin hexamer are in tensed conformation (t),which means the first eight residues of b-chain are in an extended conformation). cu2+ complex,though it assumes t6 conformation,has more structural differences due to lowering of crystal symmetry and space group shift from h3 (hexagonal crystal system) to p3 (trigonal crystal system) and a doubling of the c axis. 2ni2+ human insulin when compared to 4ni2+ arg insulin suggests that terminal modifications may be responsible for additional metal binding. all the three metals have been shown to have a role in diabetes and hence may be therapeutically useful. copyright © 2011 bentham science publishers ltd.