Hemi‐methylated oriC DNA binding activity found in non‐specific acid phosphatase

Abstract

SummaryThe lacZ -hobH fusion clone, containing an Escherichia coli DNA segment located at 92 min on the chromosomal map, was screened as a producer of E. coli oriC hemi-methylated binding activity. We have purified the protein encoded by this locus to near homogeneity. The protein corresponds to the monomeric form of a non-specific acid phosphatase (NAP) whose gene has been designated aphA. oriC DNA footprinting experiments showed protection of hemi-methylated probe by partially purified NAP, but not by purified preparations. Yet, gel retardation experiments with an oriC oligonucleotide demonstrated DNA binding activity of purified NAP in the presence of Mg 2þ . This experiment also showed an increased affinity of the protein for the hemi-methylated probe compared with the fully or unmethylated form. Indirect immunofluorescence microscopy revealed the existence of discrete NAP foci at mid-cell in cells with two nucleoids, but at cell poles in those with one nucleoid.

The First Structure of a Bacterial Class B Acid Phosphatase Reveals Further Structural Heterogeneity Among Phosphatases of the Haloacid Dehalogenase Fold

“…5 In E. coli AphA could play a similar role, 6 but it has also been involved in the parental strand recognition of the DNA replication origin. 7 No information is available for the class B acid phosphatases produced by other bacterial species. However, finding of these enzymes only in some bacterial pathogens could suggest some role in microbial pathogenicity.…”

Glutamine Phosphoribosylpyrophosphate Amidotransferase-independent Phosphoribosyl Amine Synthesis from Ribose 5-Phosphate and Glutamine or Asparagine

“…Localization studies showed that AphA is present in the cytoplasm in addition to its predominant location in the periplasm (22); thus, is it rational to suggest some PRA is generated by the mechanism described herein. Previous work in our laboratory has emphasized the multiple inputs to PRA formation (9,10,23).…”

Genetic rearrangements in the tyrB-uvrA region of the enterobacterial chromosome: a potential cause for different class B acid phosphatase regulation in Salmonella enterica and Escherichia coli

“…If the involvement in chromosomal DNA replication proposed for the class B NAP of E. coli [10] should be retained also in other species, it would be interesting to understand the signi¢cance of the heterogeneous pattern of class B NAP gene expression observed among Enterobacteriaceae to this fundamental step of microbial physiology.…”