## 1 Introduction  
An increase in the frequency and toxicity of cyanobacterial blooms in aquatic environments, mainly in freshwater reservoirs, has been recognized as an emerging health problem [1, 2]. Cyanobacterial blooms are often accompanied by a variety of cyanotoxins that have different structures and compositions that define their effects. According to the target organ, they are classified as hepatotoxins, neurotoxins, or dermatoxins, and they are produced by a variety of species from different genera [3, 4]. Microvstins (MCs), one of the most common cyanotoxins, are produced by different genera of cyanobacteria and are considered to be a potent hepatotoxin with a wide range of effects [5, 6]. They are cyclic heptapeptides, and most of them are hydrophilic due to carboxylic acids at positions 3 and 6, and to arginine, which is frequently found at positions 2 and 4 [5]. However, structural modifications due to amino acid combinations can change the polarity of a peptide. MCs are a diverse group of toxins since variations in functional groups by methylation/demethylation, hydroxylation, and epimerization generate a wide variety of congeners; to date, more than 270 variants have been described [5, 6, 7]. The marked differences in the toxicity of MC congeners are related to their chemical characteristics and their ability to distribute in different cellular compartments, according to their affinity to specific molecules. Therefore, toxicity among congeners can vary by several orders of magnitude [8]. The diversity of MCs is also related to different effects documented for this group of toxins, which include inducing apoptosis or cell proliferation [9], cancer development [10], inflammatory processes [11], metabolic disorders [12], and reproductive and neuronal alterations [13]. MCs induce DNA damage, mitochondrial dysfunction, cytoskeleton disruption, endoplasmic reticulum disruption, and cell cycle dysregulation, among other processes [4; 14; 15]. The different toxic effects of MCs appear to be dose- and time-dependent. However, the molecular factors that induce the different biochemical and cellular effects have not been fully elucidated [12; 15]. The molecular mechanisms involved in the toxicodynamics of MC congeners need to be determined to understand the processes that regulate signaling pathways, leading to cellular responses. The affinity of MC congeners to specific molecules is one of the principal elements in an evaluation that defines their mechanisms of action and toxicity. Most of these processes are difficult to evaluate through chemical and physiological experimental approaches. In contrast, computational chemistry is an important, rapid, and safe tool to decipher the interaction of toxins with target molecules and to infer their mechanisms of action. This approach evaluates docking interactions between congeners and molecular targets, and affinity scores are generated for different protein sites and configurations. In silico methods can be used to investigate multiple subprocesses and to evaluate accurate predictions of ligand binding energy as well as represent an efficient tool for screening ligand processes [16]. Therefore, potential candidate molecules can be identified for experimental validation. Currently, one of the most extensively used docking tools is AutoDock Vina (Molecular Graphics Lab, The Scripps Research Institute, La Jolla, CA, USA. [[https://vina.scripps.edu/](https://vina.scripps.edu/)]([https://vina.scripps.edu/](https://vina.scripps.edu/))). This new generation software has significantly improved the average accuracy of binding mode predictions. Vina software offers a fast search method by using a simple scoring function and provides reproducible results for large systems with more than 20 flexible links [16]. Molecular docking is a direct approach to evaluate each MC congener's affinity to the active site of enzymes.