FTIR and NMR studies on the hydration of a high-Mr subunit of glutenin

P. S. Belton, I. J. Colquhoun*, A. Grant, N. Wellner, J. M. Field, P. R. Shewry, A. S. Tatham

*Awdur cyfatebol y gwaith hwn

Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

186 Dyfyniadau (Scopus)

Crynodeb

The hydration behaviour of a purified high-Mr subunit of glutenin has been studied using Fourier transform infra-red (FTIR) and nuclear magnetic resonance (NMR) spectroscopy. The water-insoluble protein was examined in an unalkylated form with intermolecular disulfide bonds, and in a reduced and alkylated (unpolymerized) form. Hydration produced a marked increase in chain mobility, especially above a threshold water content of about 37% w/w. NMR experiments also showed that some parts of the chain were held in a much less mobile state, even at higher water contents. Little difference could be seen between alkylated and unalkylated subunits, implying that NMR is sensitive to localized motions, but not to any restrictions imposed by disulfide bridges close to the chain ends. FTIR spectra of the protein films have shown that increasing hydration enables changes to occur in favour of a more extended and β-sheet-type structure. The changes in secondary structure are very noticeable at water contents corresponding to the NMR mobility threshold. The behaviour is influenced by intermolecular interactions. β-sheet formation is enhanced by the presence of disulfide bonds in the unalkylated samples. There is little evidence of β-structure (sheet or extended chain) either in the dry state, where protein-protein interactions are strongest, or in dilute acetic acid solution, where the interactions are weakest. The balance between protein-protein and protein-water hydrogen-bonding interactions therefore appears to influence the formation of β-sheet and extended chain structures, and these may in turn affect the elasticity of high Mr subunits.

Iaith wreiddiolSaesneg
Tudalennau (o-i)74-80
Nifer y tudalennau7
CyfnodolynInternational Journal of Biological Macromolecules
Cyfrol17
Rhif cyhoeddi2
Dynodwyr Gwrthrych Digidol (DOIs)
StatwsCyhoeddwyd - 1995
Cyhoeddwyd yn allanolIe

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