According to Bieder's Dictionary of Jewish Surnames in the Russian Empire:
Turkovich and phonetic variants derive from the village of Turkovichi.
Turchanovskiy is listed as a variant of Turchinskiy and Turchanskiy, derived from the village of Turchino or Turchiny.
Beider is not always right, but his work is right more often than wrong. The point being, the dictionary lists both surnames, and shows them as being different, not variants of each other.
Damesek (Nesvizh), Braverman (Nesvizh), Kartorzynski (Nowogrudek, Korelitz, Negnewicze), Sinienski (Negnewicze, Lyubcha)