Fig. 3

Modeling structure analysis of the reported three missense mutation Ser139Tyr (upper rows), Gln8Arg (Middel rows) and Gly308Arg (bottom rows). a the backbone of the wild type residue Ser139 form three hydrogen bonds with Phe135 and Val136 (shown as red dotted line), whereas (b) the mutated Tyr139 predicted to delete the third hydrogen bond between its side chain and the Val136 backbone and create a steric clash with the Phe208 (shown as black dotted line). c the Gln88 (polar amino acid (yellow)) is surrounded only by polar and nonpolar (grey) residues. Its substitution by Lys88 (d) introduced a basic amino acid in a region which tolerate only uncharged residue. For atom representation, acid residues are colored in red, basic in blue, polar in yellow and non-polar in grey. Electrostatic potentials were calculated using ionic strengths corresponding to 0 mM ion concentration and εP = 4 before (e) and after (bf) mutation (Gly308Arg) introduction. The mutated residue, buried in the transmembrane domain, introduce an important positive charge in the core of the proteine