Galatasaray have completed the signing of teenage defender Koray Gunter from Borussia Dortmund for a fee of €2.5million.
The Germany Under-19 international has made just one Bundesliga appearance for Jurgen Klopp's side, as a substitute at Borussia Monchengladbach in October.
He has now moved to Istanbul on a four-and-a-half-year deal, although Dortmund have an option to buy the player back for a fee of €7m in the 2015-16 season.
For now, the 19-year-old centre-back, who represented Turkey at Under-16 level before switching allegiance to Germany, faces the challenge of trying to force his way into Roberto Mancini's side.
Mancini has allowed Morocco forward Nordin Amrabat to join La Liga strugglers Malaga on loan until the end of the season.
Armindo Bruma has also made a loan move away from Galatasaray after agreeing to join Super Lig rivals Gaziantepspor.
In addition, versatile Spaniard Albert Riera has left the Turk Telekom Arena after his contract was cancelled by mutual consent.