title: Metal induced conformational changes in human insulin: crystal structures of Sr2+, Ni2+ and Cu2+ complexes of human insulin.
abstract: Crystal structures of Sr(2+), Ni(2+) and Cu(2+) of human insulin complexes have been determined. The structures of Sr(2+) and Ni(2+) complexes are similar to Zn(2+) 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). Cu(2+) 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. 2Ni(2+) human insulin when compared to 4Ni(2+) 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.
authors.affiliation: CAS in Crystallography and Biophysics, University of Madras, Chennai, India.
authors.forename: Nagampalli Raghavendra Sashi
authors.initials: NR
authors.lastname: Krishna
authors.forename: Vasantha
authors.initials: V
authors.lastname: Pattabhi
authors.forename: S S
authors.initials: SS
authors.lastname: Rajan
mesh_terms: D000595:Amino Acid Sequence; D001665:Binding Sites; D002413:Cations, Divalent / Q000737:chemistry; D003300:Copper / Q000737:chemistry; D018360:Crystallography, X-Ray; D004220:Disulfides / Q000737:chemistry; D006801:Humans; D006860:Hydrogen Bonding; D007328:Insulin / Q000737:chemistry*; D008670:Metals / Q000737:chemistry*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009532:Nickel / Q000737:chemistry; D011485:Protein Binding; D011487:Protein Conformation; D013324:Strontium / Q000737:chemistry; D013329:Structure-Activity Relationship
chemical_list: D002413:Cations, Divalent; D004220:Disulfides; D007328:Insulin; D008670:Metals; D003300:Copper; D009532:Nickel; D013324:Strontium