In [1]: from shapely.geometry import Point
In [2]: import geopandas as gpd

In [3]: shapely_polygon = Polygon([(0, 0), (0, 1), (1, 0)])

In [4]: gpd.GeoSeries([shapely_polygon]).__geo_interface__
Out[4]: 
{'bbox': (0.0, 0.0, 1.0, 1.0),
 'features': [{'bbox': (0.0, 0.0, 1.0, 1.0),
   'geometry': {'coordinates': (((0.0, 0.0),
      (0.0, 1.0),
      (1.0, 0.0),
      (0.0, 0.0)),),
    'type': 'Polygon'},
   'id': '0',
   'properties': {},
   'type': 'Feature'}],
 'type': 'FeatureCollection'}