title: Chlamydia pneumoniae AP endonuclease IV could cleave AP sites of double- and single-stranded DNA.
abstract: Endonuclease IV gene, the only putative AP endonuclease of C. pneumoniae genome, was cloned into pET28a. Recombinant C. pneumoniae endonuclease I V (CpEndoIV) was expressed in E. coli and purified to homogeneity. CpEndoIV has endonuclease activity against apurinic/apyrimidinic sites (AP sites) of double-stranded (ds) oligonucleotides. AP endonuclease activity of CpEndoIV was promoted by divalent metal ions Mg2+ and Zn2+, and inhibited by EDTA. The natural (A, T, C and G) and modified (U, I and 8-oxo-G (GO)) bases opposite AP site had little effect on the cleavage efficiency of AP site of ds oligonucleotides by CpEndoIV. However, the CpEndoIV-dependent cleavage of AP site opposite modified base GO was strongly inhibited by Chlamydia DNA glycosylase MutY. Interestingly, the AP site in single-stranded (ss) oligonucleotides was also the effective substrate of CpEndoIV. Similar to E. coli endonuclease IV, AP endonuclease activity of CpEndoIV was also heat-stable to some extent, with a half time of 5 min at 60 degrees C.
authors.affiliation: College of Life Sciences and Technology, Shanghai Jiaotong, University, No. 1954 Hua-Shan Road, Shanghai 200030, China.
authors.forename: Xipeng
authors.initials: X
authors.lastname: Liu
authors.forename: Jianhua
authors.initials: J
authors.lastname: Liu
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry* / Q000378:metabolism; D016993:Chlamydophila pneumoniae / Q000201:enzymology*; D004277:DNA, Single-Stranded / Q000737:chemistry* / Q000378:metabolism; D043603:DNA-(Apurinic or Apyrimidinic Site) Lyase / Q000737:chemistry* / Q000378:metabolism; D043223:Deoxyribonuclease IV (Phage T4-Induced) / Q000737:chemistry / Q000378:metabolism; D006358:Hot Temperature; D008274:Magnesium / Q000737:chemistry / Q000378:metabolism; D011489:Protein Denaturation; D015032:Zinc / Q000737:chemistry / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D004277:DNA, Single-Stranded; D043223:Deoxyribonuclease IV (Phage T4-Induced); D043603:DNA-(Apurinic or Apyrimidinic Site) Lyase; D008274:Magnesium; D015032:Zinc