ISSN:
0887-3585
Keywords:
circular dichroism
;
secondary structure
;
insulin
;
insulin analogs
;
Chemistry
;
Biochemistry and Biotechnology
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Medicine
Notes:
Vacuum UV circular dichroism spectra measured down to 178 nm for hexameric 2-zinc human insulin, zinc-free human insulin, and the two engineered and biologically active monomeric mutants, [B/S9D] and [BS9D, T27E] human insulin, show significant differences. The secondary structure analysis of the 2-zinc human insulin (T6) in neutral solution was determined: 57% helix, 1% β-strand, 18% turn, and 24% random coil. This is very close to the corresponding crystal structure showing that the solution and solid structures are similar. The secondary structure of the monomer shows a 10-15% increase in antiparallel β-structure and a corresponding reduction in random coil structure. These structural changes are consistent with an independent analysis of the corresponding difference spectra. The advantage of secondary structure analyses of difference spectra is that the contribution of odd spectral features stemming mainly from side chain chromophores is minimized and the sensitivity of the analyses improved. Analysis of the CD spectra of T6 2-zinc, zinc-free human insulin and monomeric mutant insulin by singular value decomposition indicates that the secondary structure changes following the dissociation of hexamers into dimers and monomers are two-state processes.
Additional Material:
5 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/prot.340080309
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