  The computer artificial intelligence system AlphaFold has recently predicted
previously unknown three-dimensional structures of thousands of proteins.
Focusing on the subset with high-confidence scores, we algorithmically analyze
these predictions for cases where the protein backbone exhibits rare
topological complexity, i.e. knotting. Amongst others, we discovered a
$7_1$-knot, the most topologically complex knot ever found in a protein, as
well several 6-crossing composite knots comprised of two methyltransferase or
carbonic anhydrase domains, each containing a simple trefoil knot. These deeply
embedded composite knots occur evidently by gene duplication and
interconnection of knotted dimers. Finally, we report two new five-crossing
knots including the first $5_1$-knot. Our list of analyzed structures forms the
basis for future experimental studies to confirm these novel knotted topologies
and to explore their complex folding mechanisms.
