Towards understanding of plant mitochondrial VDAC proteins: an overview of bean (Phaseolus) VDAC proteins

As the main grain legume consumed worldwide, the common bean (Phaseolus vulgaris) is generally considered as a model for food legumes. The mitochondrial voltage-dependent anion-selective channel (VDAC) is the major transport pathway for inorganic ions, metabolites, and tRNA, and consequently it controls the exchange of these compounds between the cytoplasm and the mitochondrion. Two VDAC isoforms of Phaseolus coccineus have been investigated experimentally. However, plant VDACs are known to belong to a small multigenic family of variable size. Here, we combine available experimental as well as genomic and transcriptomic data to identify and characterize the VDAC family of Phaseolus vulgaris. To this aim, we review the current state of our knowledge of Phaseolus VDAC functional and structural properties. The genomic and transcriptomic data available for the putative VDACs of Phaseolus vulgaris are studied using bioinformatics approach including homology modelling. The obtained results indicate that five out of the seven putative VDAC encoding sequences (named PvVDAC1–5) share strongly conserved motifs and structural homology with known VDACs. Notably, PvVDAC4 and PvVDAC5 are very close to the two abundant and characterized experimentally VDAC isoforms purified from Phaseolus coccineus mitochondria.