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Molecular Mechanism Underlying ATP-Induced Conformational Changes in the Nucleoprotein Filament of Mycobacterium

G P Manjunath1,2, Neelesh Soni3, Pavana L Vaddavalli2

  • 1Department of Biochemistry, Indian Institute of Science (IISc) , Bangalore 560012, India.

Biochemistry
|February 27, 2016
PubMed

Insights

RecA protein

Area of Science:

  • Molecular Biology
  • Biochemistry

Background:

  • RecA protein is crucial for bacterial DNA repair and recombination.
  • ATP binding and specific glutamine residues (Gln196) are vital for active RecA filament formation.
  • The precise mechanism of ATP-dependent structural transitions in RecA remains unclear.

Purpose of the Study:

  • To elucidate the mechanism of ATP-dependent structural transitions in Mycobacterium smegmatis RecA (MsRecA).
  • To investigate the role of conserved residues, particularly Gln196 and Arg198, in RecA activation and filament formation.

Main Methods:

  • Biochemical analyses of MsRecA variants with mutations in conserved residues.
  • Crystallographic analysis of MsRecA variants.

Main Results:

  • The disposition of the interprotomer interface is identified as the structural basis for allosteric activation of RecA.
  • Conserved amino acids contribute to ATP hydrolysis and the transition from collapsed to extended filament forms.
  • Gln196, Arg198, and Phe219 play roles in ATP hydrolysis within the active extended filament.

Conclusions:

  • The study proposes a model for RecA activation based on interprotomer interface dynamics.
  • Specific residues are critical for both inactive and active states of RecA, influencing ATP hydrolysis and filament structure.
  • The primary nucleotide binding site in MsRecA isomerizes to form the ATP binding site in the extended filament.

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