A short carboxyl-terminal tail is required for single-stranded DNA binding, higher-order structural organization, and stability of the mitochondrial single-stranded annealing protein Mgm101.

ABSTRACT: Mgm101 is a Rad52-type single-stranded annealing protein (SSAP) required for mitochondrial DNA (mtDNA) repair and maintenance. Structurally, Mgm101 forms large oligomeric rings. Here we determine the function(s) of a 32-amino acid carboxyl-terminal tail (Mgm101(238-269)) conserved in the Mgm101 family of proteins. Mutagenic analysis shows that Lys-253, Trp-257, Arg-259, and Tyr-268 are essential for mtDNA maintenance. Mutations in Lys-251, Arg-252, Lys-260, and Tyr-266 affect mtDNA stability at 37°C and under oxidative stress. The Y268A mutation severely affects single-stranded DNA (ssDNA) binding without altering the ring structure. Mutations in the Lys-251-Arg-252-Lys-253 positive triad also affect ssDNA binding. Moreover, the C-tail alone is sufficient to mediate ssDNA binding. Finally,

SUBMITTER: Mbantenkhu M 

PROVIDER: S-EPMC3655812 | biostudies-literature | 2013 May

REPOSITORIES: biostudies-literature