Estimation of partition coefficients of Fe-S/Se protein models

BIOL 205

Francisco Torrens, Francisco.Torrens@uv.es, Institut Univesitari de Ciencia Molecular, Universitat de Valencia, Edifici d'Instituts de Paterna, P. O. Box 22085, Valencia, 46071, Spain and Gloria Castellano, Facultad de Ciencias Experimentales, Universidad Católica de Valencia San Vicente Mártir, Guillem de Castro-94, Valencia, 46003, Spain.
The SCAP method allows a semiquantitative estimation of the partitioning of many solutes between pairs of solvents. The organic solvent-water partition coefficients P are calculated. For Fe_4S_4Cys_n, the organic solvent-water partition coefficients for 1-octanol P_o, cyclohexane P_ch and chloroform P_cf decrease 4.46, 6.25 and 4.60 per Cys, respectively. P_o are in line with CDHI calculations, and P_ch-cf, with calculations performed with a method by Leo-Hansch. LogP_o-ch-cf mean relative errors are -17%, 25% and -17%, which represent mean and unsigned relative errors of -3% and 20%. On varying the number of Cys, the structures show hydrophobic moments indicative of amphipathic structures. For Se substitutions in Fe_4Se_4Cys_n, P_o-ch-cf decrease 4.52, 6.30 and 4.66 per Cys. With the reference calculations P_o-ch-cf decrease 4.03, 4.80 and 5.76 per Cys. The results for Fe_4S_(4-m)Se_mCys_4 suggest a role of FeSe clusters in physiological processes.
 

Frontiers in Chemical Biology
5:00 PM-7:00 PM, Wednesday, August 22, 2007 BCEC -- Exhibit Hall - B2, Poster

Division of Biological Chemistry

The 234th ACS National Meeting, Boston, MA, August 19-23, 2007