Structure-Function Analysis of the Phosphoesterase Component of the Nucleic Acid End-Healing Enzyme Runella slithyformis HD-Pnk.

ABSTRACT: Runella slithyformis HD-Pnk is the prototype of a family of dual 5' and 3' nucleic acid end-healing enzymes that phosphorylate 5'-OH termini and dephosphorylate 2',3'-cyclic-PO₄, 3'-PO₄, and 2'-PO₄ ends. HD-Pnk is composed of an N-terminal HD phosphohydrolase module and a C-terminal P-loop polynucleotide kinase module. Here, we probed the phosphoesterase activity of HD-Pnk by querying its ability to hydrolyze non-nucleic acid phosphoester substrates and by conducting a mutational analysis of conserved amino acid constituents of the HD domain. We report that HD-Pnk catalyzes vigorous hydrolysis of p-nitrophenylphosphate (K_m = 3.13 mM; k_cat = 27.8 s^-1) using copper as its metal cofactor. Mutagenesis

SUBMITTER: Munir A 

PROVIDER: S-EPMC6657592 | biostudies-literature | 2019 Aug

REPOSITORIES: biostudies-literature