Open AccessA Novel Replicative Enzyme Encoded by the Linear Arthrobacter Plasmid pAL1
Author(s) -
Stephan Kolkenbrock,
Bianca Naumann,
Michael Hippler,
Susanne Fetzner
Publication year - 2010
Publication title -
journal of bacteriology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.652
H-Index - 246
eISSN - 1067-8832
pISSN - 0021-9193
DOI - 10.1128/jb.00614-10
Subject(s) - biology , primase , dna polymerase , dna , helicase , microbiology and biotechnology , recombinant dna , genetics , gene , rna , reverse transcriptase
The soil bacteriumArthrobacter nitroguajacolicus Rü61a contains the linear plasmid pAL1, which codes for the degradation of 2-methylquinoline. Like other linear replicons of actinomycetes, pAL1 is characterized by short terminal inverted-repeat sequences and terminal proteins (TPpAL1 ) covalently attached to its 5′ ends. TPpAL1 , encoded by thepAL1.102 gene, interactsin vivo with the protein encoded bypAL1.101. Bioinformatic analysis of the pAL1.101 protein, which comprises 1,707 amino acids, suggested putative zinc finger and topoisomerase-primase domains and part of a superfamily 2 helicase domain in its N-terminal and central regions, respectively. Sequence motifs characteristic of the polymerization domain of family B DNA polymerases are partially conserved in a C-terminal segment. The purified recombinant protein catalyzed the deoxycytidylation of TPpAL1 in the presence of single-stranded DNA templates comprising the 3′-terminal sequence (5′-GCAGG-3′), which in pAL1 forms the terminal inverted repeat, but also at templates with 5′-(G/T)CA(GG/GC/CG)-3′ ends. Enzyme assays suggested that the protein exhibits DNA topoisomerase, DNA helicase, and DNA- and protein-primed DNA polymerase activities. The pAL1.101 protein, therefore, may act as a replicase of pAL1.