Nmr-Study on a Sryd-Containing Fibronectin-Like Sequence-(250-257) of Leishmania-Gp63 - Contribution of Residual Water in the Dimethyl-Sulfoxide Solution Structure
Nmr-Study on a Sryd-Containing Fibronectin-Like Sequence-(250-257) of Leishmania-Gp63 - Contribution of Residual Water in the Dimethyl-Sulfoxide Solution Structure
(EN)
Tsikaris, V.
(EN)
Πανεπιστήμιο Ιωαννίνων. Σχολή Θετικών Επιστημών. Τμήμα Χημείας
(EL)
Tsikaris, V.
(EN)
The conformational characteristics of the I(250)ASRYDQL(257) synthetic octapeptide, which incorporates the SRYD adhesion site (252-255) of Leishmania gp63, have been investigated at pH 2 and 5, by means of 1D and 2D H-1 NMR spectroscopy (temperature coefficient values, chemical shifts, vicinal coupling constants and NOE effects). It was found that elimination of residual water from the dimethyl sulfoxide (DMSO) solution at pH 2 provides exchange peaks in the ROESY and HOHAHA spectra similar to those obtained for the DMSO peptide solution at pH 5. This common structure is stabilized (i) by the formation of a type I beta-turn involving the QNH --> RCO interaction and (ii) by a possible interaction between the guanidinium and the D-beta-carboxylate groups. After treatment with molecular sieves, the remaining residual water is redistributed between the peptide functional groups and participates in the rigidification of the new conformational state.
(EN)
