Characterization of LdrA (Long Direct Repeat A) protein of escherichia coli

Yoshihiro Yamaguchi, Narumi Tokunaga, Masayori Inouye, Sangita Phadtare

Research output: Contribution to journalArticlepeer-review

11 Scopus citations


Reminiscent of apoptotic genes in higher systems, almost all bacteria contain 'suicide' genes, which encode toxins. Toxins inhibit cell growth and may cause cell death. These are coexpressed with their cognate antitoxins from a toxin-antitoxin (TA) operon in normally growing cells. The cellular targets of toxins are diverse. The study of the TA system is important as in addition to their involvement in the normal bacterial physiology, TA systems may also play a role in bacterial pathogenicity. The long direct repeat (Ldr) family of proteins belongs to one such TA system. Here we report characterization of LdrA, the prototypical protein of the Ldr family, and show that it is highly toxic for cell growth. The data suggests that LdrA may exert toxicity by inhibiting ATP synthesis, possibly due to its localization in the cell membrane. This inhibition of energy production leads to the inhibition of biosynthetic reactions in the cell such as DNA replication, transcription and translation, and eventually cell growth.

Original languageEnglish (US)
Pages (from-to)91-97
Number of pages7
JournalJournal of Molecular Microbiology and Biotechnology
Issue number2
StatePublished - Jun 2014
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Biotechnology
  • Microbiology
  • Applied Microbiology and Biotechnology
  • Molecular Biology


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