No, the exclusion is not prorated, so the only tax will be on the depreciation (assuming the rest of the Gain is less than $250,000/$500,000).
However, based on your previous question, the TurboTax step-by-step interview is not set up to report this sale because the Fair Market Value (when it was converted to a rental) was lower than your Cost Basis. You may consider going to a tax professional to have it reported correctly.