biostudies-literatureSomarajan SRNIA NIH HHSNIAID NIH HHSNCI NIH HHS1821-31https://www.ebi.ac.uk/biostudies/studies/S-EPMC3013625biostudies-literatureUnknown12(12)We identified Mpn133 as a Ca(2+)-dependent cytotoxic nuclease of Mycoplasma pneumoniae. Flow cytometry analysis and immunofluorescence studies revealed the binding and internalization of recombinant Mpn133 (rMpn133) in human airway A549 cells. Amino acid sequence comparisons of Mpn133 with other mycoplasma nucleases demonstrated the presence of a unique glutamic acid-, lysine- and serine-rich region (EKS region; amino acids 72-110). Deletion of this EKS peptide (rMpn133(Δ72-110)) abrogated its binding and internalization but not its nuclease activity. The function of the EKS region in host cell trafficking and nuclear localization was reinforced by the successful delivery of EKS-conjugated mCherry protein into A549 cells. rMpn133, but not rMpn133(Δ72-110), induced apoptosis-like death in ACellular microbiologyMycoplasma pneumoniae Mpn133 is a cytotoxic nuclease with a glutamic acid-, lysine- and serine-rich region essential for binding and internalization but not enzymatic activity.PMC3013625P30 AG013319U19 AI070412P30 CA054174P01 AG019316P01 AG19316P30 CA54174Kannan TRSomarajan SRBaseman JBfalseMycoplasma pneumoniae Mpn133 is a cytotoxic nuclease with a glutamic acid-, lysine- and serine-rich region essential for binding and internalization but not enzymatic activity.We identified Mpn133 as a Ca(2+)-dependent cytotoxic nuclease of Mycoplasma pneumoniae. Flow cytometry analysis and immunofluorescence studies revealed the binding and internalization of recombinant Mpn133 (rMpn133) in human airway A549 cells. Amino acid sequence comparisons of Mpn133 with other mycoplasma nucleases demonstrated the presence of a unique glutamic acid-, lysine- and serine-rich region (EKS region; amino acids 72-110). Deletion of this EKS peptide (rMpn133(Δ72-110)) abrogated its binding and internalization but not its nuclease activity. The function of the EKS region in host cell trafficking and nuclear localization was reinforced by the successful delivery of EKS-conjugated mCherry protein into A549 cells. rMpn133, but not rMpn133(Δ72-110), induced apoptosis-like death in A2010-01-01T00:00:00Z2010 Dec2026-05-01T20:55:03.059Z2019-03-27T00:37:47ZS-EPMC30136252069092310.1111/j.1462-5822.2010.01513.x