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Discovery of new enzyme for cell stability

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    Science & Technology
  • Published
    11th Jun, 2021


The Centre for Cellular and Molecular Biology (CCMB) scientists have discovered an enzyme that helps maintain the stability and integrity of cell walls in bacteria such as Escherichia coli.

About the newly discovered enzyme

  • The enzyme is named as ‘LdtF’.
  • Area of action: Cell wall of gram-negative bacteria has an outer membrane and an inner membrane. In between these two layers a layer of ‘peptidoglycan’, a polymer of amino acids and sugars is also found.
  • A lipoprotein is known to link the outer membrane to the layer of peptidoglycan.
  • Function: The newly discovered enzyme, ‘LdtF’ could cleave the lipoprotein from the peptidoglycan.
  • This enzyme plays a vital role in the formation of covalent linkages between the bacterial outer membrane and an inner polymer layer of peptidoglycan, that protects bacteria from environmental stress.
  • Absence of this LdtF enhanced growth defects and increased the peptidoglycan-lipoprotein linkages in the bacteria.
  • The presence of this enzyme, however, decreased the levels of peptidoglycan-bound lipoprotein, suggesting its role in modulating the peptidoglycan-lipoprotein linkages.
  • Such LdtF-mediated modulation of the cell wall gives bacteria flexibility and a survival advantage in fluctuating environmental conditions.
  • Significance: This study will help understand the fundamental bacterial cell wall biology and identify alternate drug targets for the development of new antimicrobials.

Gram negative and Gram positive bacteria

Gram-Positive bacteria

  • A single-layered, smooth cell wall.
  • It is a thick layer of peptidoglycan and it can also be multilayered.
  • The outer membrane is absent.
  • These bacteria retain the crystal violet colour after they are washed with acetone or alcohol and appear as purple-coloured under the microscope after gram staining.

Gram-Negative bacteria

  • A double-layered, wavy cell-wall.
  • It is a thin layer or often single-layered peptidoglycan.
  • The outer membrane is present.
  • These bacteria do not retain the stain colour after washing with acetone or alcohol and appear as pink-coloured under the microscope after gram staining.