title: X-ray investigation of gene-engineered human insulin crystallized from a solution containing polysialic acid.
abstract: Attempts to crystallize the noncovalent complex of recombinant human insulin with polysialic acid were carried out under normal and microgravity conditions. Both crystal types belonged to the same space group, I2(1)3, with unit-cell parameters a = b = c = 77.365 A, alpha = beta = gamma = 90.00 degrees. The reported space group and unit-cell parameters are almost identical to those of cubic insulin reported in the PDB. The results of X-ray studies confirmed that the crystals obtained were cubic insulin crystals and that they contained no polysialic acid or its fragments. Electron-density maps were calculated using X-ray diffraction sets from earth-grown and microgravity-grown crystals and the three-dimensional structure of the insulin molecule was determined and refined. The conformation and secondary-structural elements of the insulin molecule in different crystal forms were compared.
authors.affiliation: Shubnikov Institute of Crystallography, Russian Academy of Sciences, Leninsky Prospekt 59, 119333 Moscow, Russia. tostars@mail.ru
authors.forename: V I
authors.initials: VI
authors.lastname: Timofeev
authors.forename: R N
authors.initials: RN
authors.lastname: Chuprov-Netochin
authors.forename: V R
authors.initials: VR
authors.lastname: Samigina
authors.forename: V V
authors.initials: VV
authors.lastname: Bezuglov
authors.forename: K A
authors.initials: KA
authors.lastname: Miroshnikov
authors.forename: I P
authors.initials: IP
authors.lastname: Kuranova
mesh_terms: D018360:Crystallography, X-Ray; D006801:Humans; D007328:Insulin / Q000737:chemistry* / Q000235:genetics; D008958:Models, Molecular; D020836:Protein Structure, Quaternary; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D012794:Sialic Acids / Q000737:chemistry*; D040681:Structural Homology, Protein
chemical_list: D007328:Insulin; D012794:Sialic Acids; C021319:polysialic acid