Role of C-Terminal Region of Yeast ADP/ATP Carrier 2 Protein: Dynamics of Flexible C-Terminal Arm

Background: The ADP/ATP carrier catalyzes the exchange of ADP and ATP across the inner mitochondrial membrane. Materials and Methods: The molecular dynamics of modeled yeast type 2 AAC (yAAC2) was analyzed and molecular parameters were determined. Results: The yAAC2 C-terminal moved flexibly and a negative electrostatic potential field (ESP) was located in the C-terminal region. The ESP field is always located in the C-terminal area during C-terminal truncation (d1-d9). Further C-terminal truncation occurred on field invagination into the core region (d11, d14, d16). The 2-6 C-terminal amino acid truncation did not affect the biological activity. The d7-d9 truncated mutants lost their biological function. Conclusion: A critical point in yAAC2 function was shown between d6 and d7 C-terminal truncation. The C-terminal structure of yAAC2 is thought to be involved in biological function control.