X-ray investigation of gene-engineered human insulin crystallized from a solution containing polysialic acid.
Acta Crystallogr Sect F Struct Biol Cryst Commun,
PubMed id: 20208155
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.