Molecular interactions between mitochondrial membrane proteins and the C-terminal domain of PB1-F2: an in silico approach.

PB1-F2 is a recently described influenza A viral protein that induces apoptosis by binding with two mitochondrial membrane proteins, i.e. VDAC1 (outer membrane) and ANT3 (inner membrane). Knowledge of this binding mechanism could provide insights that would aid in the design of novel inhibitors against this protein. Therefore, to better understand these interactions, we have undertaken this study to model the PB1-F2 protein of the highly pathogenic influenza A virus subtype H5N1. Moreover, a model of human ANT3 was also established. The dynamics of the molecular interactions between the C-terminal region of PB1-F2 protein and VDAC1 and ANT3 were expounded by employing an in silico approach. Our results suggest the involvement of 12 amino acids of PB1-F2 protein, which form hydrophobic contacts with 22 amino acids of VDAC1. Of these, Leu64, Arg75 and Val76 were found to be crucial for mitochondrial targetting. In the case of the PB1-F2-ANT3 complex, 14 amino acids of ANT3 were found to make hydrophobic contacts with 9 amino acids of PB1-F2. Furthermore, two hydrogen bonds were predicted in both complexes PB1-F2/VDAC1 and PB1-F2/ANT3. This study reveals the molecular interactions required for PB1-F2-induced apoptosis and suggests a hypothetical model for future study.

Isolation, nucleotide identification and tissue expression of three novel ovine genes-SLC25A4, SLC25A5 and SLC25A6.

The complete coding sequences of three of sheep genes SLC25A4, SLC25A5 and SLC25A6 were firstly amplified using the reverse transcriptase polymerase chain reaction (RT-PCR) according to the conserved sequence information of the cattle or other mammals and known highly homologous sheep ESTs. Sheep SLC25A4, SLC25A5 and SLC25A6 genes encode three corresponding proteins of 298 amino acids which contain the identically conserved putative mitochondrial carrier protein domain. Sheep SLC25A4 protein has high homology with the SLC25A4 proteins of six species-cattle (99%), human (95%), rat (95%), mouse (94%), dog (94%) and chicken (89%). Sheep SLC25A5 protein has high identity with the SLC25A5 proteins of five species-cattle (100%), dog (99%), mouse (98%), rat (98%) and human (98%). Sheep SLC25A6 protein also has high homology with the SLC25A6 proteins of four species-cattle (99%), human (97%), pig (97%) and chicken (93%). The phylogenetic tree analysis demonstrated that sheep SLC25A4, SLC25A5 and SLC25A6 proteins share a common ancestor. Moreover, SLC25A4, SLC25A5 and SLC25A6 proteins present stronger interaction each other. The tissue expression analysis indicated that sheep SLC25A4, SLC25A5 and SLC25A6 genes were expressed in a range of tissues including leg muscle, kidney, skin, longissimus dorsi muscle, spleen, heart and liver. Our experiment is the first to provide the primary foundation for further insight into these three sheep genes.