how should I choose the polypeptide subsequence

I want to synthesis a polypeptide in order to make the antiserum.This is the amino acid subsequence.

MPDWDSSLILTAYIIILLTGLPANLLALRAFLGRVRQPHPAPVH                ILLLSLTLADVLLLLLLPFKIIEAASDFRWELSNLACALMGFGFYGSIYCSTLLLAGI 
SVERYLGVAFPVQYKLSRRPVYGVIAALIAWVMSFGHGTVVIIVQYLNSTQRAPKENE                     TTCYENFTQEQLRLLLPIRLELCLLLFFFPMVVTTFCYSRFVWIMLTQPHMGAQKQRR                     AMGLAIVSLLNFLLCFGPYNISHLVGFYMKASPKWRREAVVFGSLNASLDPLLFYFSS                     SVVRRSFGKGLQALYHWGSSLLGRRCKETAEAANEDPGVSQAEGAPSSDFTLD
The underlined and red subsequence is the predicted 7 transmemberane domains.Which domain should i choose to synthesis the polypeptide.Thanks.