From the reply, it seems for me like you are looking for an excuse for not paying the taxes. I am sorry, but you will not find any here, nor should you be looking for one.
If you live in Turkey, then you do not tax towards US unless you also work in US, the reason you live in Turkey is due to your working on an abroad assignment from a US company, or have any other connection to it (like owning a company in US which is running).
In addition, if you have not already done so, you should contact the Turkish tax department and get setup with them to pay taxes and social security + setup the proper company form for your business.
Now, if you do business in both countries things start to get muddy, in this case it all depends on the tax agreements (normally called Double Tax Treaty) and social security agreements US and Turkey have.
What is important to note, is that you in most countries have to send in an application regarding the tax agreements and social security, i.e. to avoid being taxed by both countries.
In your case, you would most probably have to pay full tax to Turkey and then reduced tax in US if you actually have a "work relationship" in both countries, this is how the double tax treaties normally work, which means sometimes it can give you a higher tax as well, in the event the country you live in has a higher tax rate than the other country.