Quantum Speedup for Protein Structure Prediction

Protein structure prediction (PSP) predicts the native conformation for a given protein sequence. Classically, the problem has been shown to belong to the NP-complete complexity class. Its applications range from physics, through bioinformatics to medicine and quantum biology. It is possible however to speed it up with quantum computational methods, as we show in this paper. Here we develop a fast quantum algorithm for PSP in three-dimensional hydrophobic-hydrophilic model on body-centered cubic lattice with quadratic speedup over its classical counterparts. Given a protein sequence of n amino acids, our algorithm reduces the temporal and spatial complexities to, respectively, O(2
^{\frac n2}
) and O(n
²
logn). With respect to oracle-related quantum algorithms for the NP-complete problems, we identify our algorithm as optimal. To justify the feasibility of the proposed algorithm we successfully solve the problem on IBM quantum simulator involving 21 and 25 qubits. We confirm the experimentally obtained high probability of success in finding the desired conformation by calculating the theoretical probability estimations.