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Structural changes of met‐haemoglobin by dehydration
Author(s) -
Böhm S.,
Abaturov L.V
Publication year - 1977
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(77)80184-1
Subject(s) - citation , library science , chemistry , physics , computer science
As was emphasized by Kuntz and Kautzmann in a recent review [l] , the interpretation of absorption isotherms for water-uptake by dried proteins is difficult, for lack of experimental data about the structure of partially or fully dehydrated proteins. They suggest that the shape of absorption isotherms and their hysteresis may be determined by a ‘substantial refolding of the polypeptide chains and rearrangements of side-chains in order to reduce the size of voids created on drying a protein’. To prove this assumption, we have done parallel investigations on the influence of dehydration on the CD-spectra (190-240 mn) and the absorption spectra (300-700 mn) of Met-Hb* prepared as films. Our results show a complicated, at least biphasic, dependence of the Met-Hb structure on dehydration. Removal of the first amount of the more weakly bound water (from lOO-70% r.h.) produced a hemichrome form as indicated by absorption spectra; only minor changes are induced in the secondary structure as indicated by CD-spectra. Withdrawal of the last amount of the more strongly bound water (from 70-O% r.h.) diminished the helix content of Met-Hb by 25-30%. The conformation of the dried protein corresponds to the solution and film