I respectfully diagree with you vvr_07, changing responsibility to opportunity make a substantial change to the meaning, therefore it should be avoided.
As for the sentence I suggest something like;
Having consideredthe responsibilities this job involves, I don't think ifit is the one that I would like to have(hold/carry out)
The grammar is okay but it's far from natural sounding. Here is a better version: After consideration of its responsibilities I don't think this is a job that I can accept.