Jan, thanks a lot for sharing!
It was a Jak from 3.IAK, which was captured in the Kuban area in spring 1943. Some Russian sources say that Germans (JG3 or 52?) used them in combat with Soviet markings. But the plane is shown in a book with German painting and markings nevertheless. For details, see the book "Dragons on Birds wings". For the first time I see the bort/number "2" of the plane with its original, Soviet markings.
PS: In the "Tagebuch des Hauptmann Lifert" on page 54, two other bubbletop-Jaks are depicted: One from 3.IAK numbered "39", the other is not identifiable.
PPS: On your pic linked below, a second Jak is visible in the background:
