The lira dropped by over 11 percent in value in one day on Friday morning to almost six lira per dollar.
The lira's tailspin has unsettled global markets, with shares of European banks coming under particular pressure because of concerns over the lenders' exposure to Turkey.
The penalties also bar any U.S. transactions with the two men.
The currency, which traded 4.7 to the dollar a month ago, has now weakened to 6.4 to the dollar, having lost more than 30% of its value this month, 20% of which accrued in the last 24 hours. Aluminum will now be 20% and Steel 50%.
With the dispute intensifying, Trump on Friday doubled steel and aluminum tariffs on Turkey, sending the beleaguered lira plunging 16 percent, part of a 40 percent plummet for the currency this year.
No body, no state and no credit rating agency can threaten Turkey and Turkish people, he added.
Brunson had worked in Turkey for more than two decades, before he was arrested on terrorism charges. Financial upheaval there risks further destabilising an already volatile region.
"We can only say "good-bye" to anyone who sacrifices its strategic partnership and a half century alliance with a country of 81 million for the sake of relations with terror groups", Erdogan said.
"As he stated, the president has authorized the preparation of documents to raise tariffs on imports of steel and aluminum from Turkey", White House Deputy Press Secretary Lindsay Walters said.
In the event of contagion, Turkey's economic misfortune would likely hit its closest neighbors who are most fragile first, some market analysts said. He has denied the charges.
A delegation led by Turkish Deputy Foreign Minister Sedat Onal failed to secure a deal last Wednesday in talks in Washington on a number of issues including Mr Brunson. "This is a domestic and national struggle".
"Some countries have engaged in behaviour that protects coup plotters and knows no laws or justice", he said.
"President Erdogan's strengthened powers under the new presidential system have made it increasingly uncertain whether policymakers will be able to act to stabilize the economy", William Jackson, the chief emerging markets economist at Capital Economics in London, said. Even if Washington and Ankara can resolve their immediate problems - such as the recent arrest of USA citizens in Turkey - the numerous, and multiplying, issues on which Turkey and the United States now disagree could be their relationship's undoing.
"Before it is too late, Washington must give up the misguided notion that our relationship can be asymmetrical and come to terms with the fact that Turkey has alternatives". "Failure to reverse this trend of unilateralism and disrespect will require us to start looking for new friends and allies".
He said the crash of the lira, sparked by his bitter dispute with the United States, was a "political plot" against Turkey and warned that Ankara would now seek new markets and partners, AFP reported. Do not take a stance saying, "We are bankrupt, we are done, we should guarantee ourselves.' If you do that, that would be wrong".
Although Erdogan struck a defiant tone, his foreign ministry called for diplomacy and dialogue to solve problems with Washington and Trade Minister Ruhsar Pekcan said "we implore President Trump to return to the negotiating table". Turkey is the sixth-largest steel exporter to the United States. Gulen denies the allegation. I am addressing the U.S. once again: it is a pity that you chose a pastor over your strategic partner in North Atlantic Treaty Organisation.