Role of unique loops in oligomerization and ATPase function of Plasmodium falciparum gyrase B

Protein Sci. 2022 Feb;31(2):323-332. doi: 10.1002/pro.4217. Epub 2021 Nov 6.

Abstract

DNA gyrase is an ATP dependent Type IIA topoisomerase that is unique to prokaryotes. Interestingly DNA gyrase has also been found in the apicoplasts of apicomplexan parasites like Plasmodium falciparum (Pf) the causative agent of Malaria. Gyrase B (GyrB), a subunit of gyrase A2 B2 complex has an N-terminal domain (GyrBN) which is endowed with ATPase activity. We reported earlier that PfGyrB exhibits ATP-independent dimerization unlike its bacterial counterparts. Here we report the role of two unique regions (L1 and L2) identified in PfGyrBN. Deletions of L1 alone (PfGyrBNΔL1), or L1 and L2 together (PfGyrBNΔL1ΔL2) have indicated that these regions may play an important role in ATPase activity and the oligomeric state of PfGyrBN. Our experiments show that the deletion of L1 region disrupts the dimer interface of PfGyrBN and reduces its ATPase activity. Further through ITC experiments we show that the binding affinity of ATP to PfGyrBN is reduced upon the deletion of L1 region. We have observed a reduction in ATPase activity for of all three proteins PfGyrBN, PfGyrBNΔL1, and PfGyrBNΔL1ΔL2 in presence of coumermycin. Our results suggests that L1 region of PfGyrBN is likely to be functionally important and may provide a unique dimer interface that affects its enzymatic activity. Since deletion of L1 region decreases the affinity of ATP to the protein, this region can be targeted toward designing novel inhibitors of ATP hydrolysis.

Keywords: ATP hydrolysis; Plasmodium falciparum; binding affinity; circular dichroism; coumermycin; gyrase B; inhibition; isothermal titration calorimetry.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenosine Triphosphatases* / chemistry
  • Adenosine Triphosphatases* / genetics
  • Adenosine Triphosphate / metabolism
  • DNA Gyrase* / chemistry
  • DNA Gyrase* / genetics
  • Dimerization
  • Plasmodium falciparum* / enzymology
  • Plasmodium falciparum* / genetics
  • Protozoan Proteins* / chemistry
  • Protozoan Proteins* / genetics

Substances

  • Protozoan Proteins
  • Adenosine Triphosphate
  • Adenosine Triphosphatases
  • DNA Gyrase