TY  - JOUR
A1  - Bassam, Rasha
A1  - Hescheler, Jürgen
A1  - Temiz Artmann, Aysegül
A1  - Artmann, Gerhard
A1  - Digel, Ilya
T1  - Effects of spermine NONOate and ATP on the thermal stability of hemoglobin
JF  - BMC Biophysics
N2  - Background
Minor changes in protein structure induced by small organic and inorganic molecules can result in significant metabolic effects. The effects can be even more profound if the molecular players are chemically active and present in the cell in considerable amounts. The aim of our study was to investigate effects of a nitric oxide donor (spermine NONOate), ATP and sodium/potassium environment on the dynamics of thermal unfolding of human hemoglobin (Hb). The effect of these molecules was examined by means of circular dichroism spectrometry (CD) in the temperature range between 25°C and 70°C. The alpha-helical content of buffered hemoglobin samples (0.1 mg/ml) was estimated via ellipticity change measurements at a heating rate of 1°C/min.

Results
Major results were:
1) spermine NONOate persistently decreased the hemoglobin unfolding temperature T u irrespectively of the Na + /K + environment,
2) ATP instead increased the unfolding temperature by 3°C in both sodium-based and potassium-based buffers and
3) mutual effects of ATP and NO were strongly influenced by particular buffer ionic compositions. Moreover, the presence of potassium facilitated a partial unfolding of alpha-helical structures even at room temperature.

Conclusion
The obtained data might shed more light on molecular mechanisms and biophysics involved in the regulation of protein activity by small solutes in the cell.
KW  - Nitric Oxide Donor
KW  - NONOate
KW  - Circular Dichroism
KW  - Nitric Oxide
Y1  - 2012
U6  - http://dx.doi.org/10.1186/2046-1682-5-16
SN  - 2046-1682
VL  - 5
PB  - BioMed Central
CY  - London
ER  -