NAD-dependent protein deacetylase, which is involved in repression of RNA polymerase I-mediated expression immediately adjacent to telomeres. It is however not involved in antigenic variation and subtelomeric variant surface glycoprotein (VSG) gene silencing. Plays a role in DNA damage response. Also has ADP-ribosylation activity in vitro. H2O + N(6)-acetyl-L-lysyl-[protein] + NAD(+) = 2''-O-acetyl-ADP-D-ribose + L-lysyl-[protein] + nicotinamide Binds 1 zinc ion per subunit. Co-localizes with telomeres and minichromosomes. Belongs to the sirtuin family. Class I subfamily.