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Nono Saha, C. M.

Publications and source records attributed to Nono Saha, C. M..

2 recordsLinked to original sources

An evolutionary algorithm for inverse RNA folding inspired by Levy flights

A Levy flight is a random walk with step sizes that follow a heavy-tailed probability distribution. This type of random walk, with many small steps and a few large ones, has inspired many applications in genetic programming and evolutionary algorithms in recent years, but is yet to be applied to RNA design. Here we study the inverse folding problem for RNA, viz. the discovery of sequences that fold into given target secondary structures. We implement a Levy mutation scheme in an updated version of aRNAque, an evolutionary inverse folding algorithm, and apply it to the design of RNAs with and without pseudoknots. We find that the Levy mutation scheme increases the diversity of designed RNA sequences and reduces the average number of evaluations of the evolutionary algorithm. The results show improved performance on both Pseudobase++ and the Eterna100 datasets, outperforming existing inverse folding tools. We propose that a Levy flight offers a better standard mutation scheme for optimizing RNA design.

bioinformatics↗

RAFFT: Efficient prediction of RNA folding pathways using the fast Fourier transform

We propose a novel heuristic to predict RNA secondary structure formation pathways that has two components: (i) a folding algorithm and (ii) a kinetic ansatz. This heuristic is inspired by the kinetic partitioning mechanism, by which molecules follow alternative folding pathways to their native structure, some much faster than others. Similarly, our algorithm RAFFT starts by generating an ensemble of concurrent folding pathways ending in multiple metastable structures, which is in contrast with traditional thermodynamic approaches that find single structures with minimal free energies. When we constrained the algorithm to predict only 50 structures per sequence, nearnative structures were found for RNA molecules of length [≤] 200 nucleotides. Our heuristic has been tested on the coronavirus frameshifting stimulation element (CFSE): an ensemble of 68 distinct structures allowed us to produce complete folding kinetic trajectories, whereas known methods require evaluating millions of sub-optimal structures to achieve this result. Thanks to the fast Fourier transform on which RAFFT is based, these computations are efficient, with complexity [O](L2 log L).

bioinformatics↗