Draw the complementary circle part

Question

My intention is to represent the molecular docking in a very schematic way. What you see here is the protein, and the cavity represents its active site. To represent the ligand molecule I would need to draw, in a separate image, the complementary part of the circle. Maybe, also a method to obtain the same image without having to rotate it. Any ideas?

\documentclass{standalone}
\usepackage{tikz}
\begin{document}
    \begin{tikzpicture}
            \filldraw[fill opacity=0.5,fill=blue,rotate=23] (0,0) -- (4,0) arc (0:315:4.0cm) -- cycle;      
    \end{tikzpicture}
\end{document}

Answer 1

\documentclass[tikz, border=1cm]{standalone}
\begin{document}
\begin{tikzpicture}
\fill[blue!50] (0,0) -- (23:4) arc[start angle=23, end angle=360-23, radius=4] -- cycle;
\fill[blue!50, xshift=10cm] (0,0) -- (23:4) arc[start angle=23, end angle=-23, radius=4] -- cycle;
\fill[blue!50, yshift=-10cm] (-4,-4) rectangle (4,4) (0,0) -- (23:4) arc[start angle=23, end angle=360-23, radius=4] -- cycle;
\fill[blue!50, xshift=10cm, yshift=-10cm, even odd rule] (0,0) -- (23:4) arc[start angle=23, end angle=360-23, radius=4] -- cycle (1.2,2.5) circle[radius=0.8];
\fill[xshift=10cm, yshift=-10cm] (1,2.4) circle[radius=0.4];
\end{tikzpicture}
\end{document}