The eukaryotic subtilisin prohormone convertase 2 (PC2) is known to require in vivo exposure to the neuroendocrine protein 7B2 in order to produce an enzymatically active species capable of proteolytic action on prohormone substrates. In the present study, we examined the role of the pentabasic site within 27-kDa 7B2 in this process. We prepared two His-tagged recombinant 7B2s by overexpression...

The cleavage of a DNA phosphodiester bond by Escherichia coli DNA topoisomerase I and the simultaneous covalent linkage of the enzyme to the 5’-phosphoryl group of the DNA at the cleavage site have been reported previously (Depew, R. E., Liu, L. F., and Wang, J. C. (1978) J. Biol. Chem 253, 511-518; Liu, L. F., and Wang, J. C. (1979) J. Biol. Chem 254, 11082-11088). With either E. coli or Micmc...

Using the P4 unknotting assay, DNA topoisomerase I1 has been purified from several mammalian cells. Similar to prokaryotic DNA gyrase, mammalian DNA topoisomerase I1 can cleave double-stranded DNA and be trapped as a covalent protein-DNA complex. This cleavage reaction requires protein denaturant treatment of the topoisomerse 11-DNA complex and is reversible with respect to salt and temperature...

FokI is a type IIs restriction endonuclease comprised of a DNA recognition domain and a catalytic domain. The structural similarity of the FokI catalytic domain to the type II restriction endonuclease BamHI monomer suggested that the FokI catalytic domains may dimerize. In addition, the FokI structure, presented in an accompanying paper in this issue of Proceedings, reveals a dimerization inter...

two newly-created water-soluble complexes of palladium(ii)/platinum(ii)-dithiocarbamate, [pd/pt(phen)(pyr-dtc)]no3 (phen = 1,10-phenanthroline and pyr-dtc = pyrrolidinedithiocarbamate) were synthesized. also, their chemical characteristics are reported in the current research paper. in these complexes, the dithiocarbamato ligand coordinates to pt(ii) or pd(ii) center with two sulfur atoms as bi...

During cut-and-paste mariner/Tc1 transposition, transposon DNA is cut precisely at its junction with flanking DNA, ensuring the transposon is neither shortened nor lengthened with each transposition event. Each transposon end is flanked by a TpA dinucleotide: the signature target site duplication of mariner/Tc1 transposition. To establish the role of this sequence in accurate DNA cleavage, we h...