I'm looking at the, recently made public,
DOC books and I can say this much:
1) It cannot be
Sear 2273 because that one has
Christ on the
obverse. Yours has the
Virgin Mary.
2) I don't think It's
Sear 2290 because the throne on the
reverse for that is pretty high up (has a back to it), and yours seems like it doesn't have that feature.
3) Looking at Example C.15 - 88 from
DOC Volume 5-2, which looks very similar to yours (in the details of the coin), I would say that yours is
Sear 2274
The other option is
Sear 2275, but that brings similar issues to #2, and you can't really see if the
Virgin Mary has her right
arm extended as with her left on your coin.
Just my two cents; first time looking at
Paleologian coins.