The nucleotide specificity of succinyl-CoA synthetase of Plasmodium falciparum is not determined by charged gatekeeper residues alone.

Autor: Vashisht K; Protein Biochemistry and Engineering Lab, Parasite-Host Biology Group, ICMR-National Institute of Malaria Research, New Delhi, India., Singh P; Protein Biochemistry and Engineering Lab, Parasite-Host Biology Group, ICMR-National Institute of Malaria Research, New Delhi, India., Verma S; Protein Biochemistry and Engineering Lab, Parasite-Host Biology Group, ICMR-National Institute of Malaria Research, New Delhi, India., Dixit R; Protein Biochemistry and Engineering Lab, Parasite-Host Biology Group, ICMR-National Institute of Malaria Research, New Delhi, India., Mishra N; Protein Biochemistry and Engineering Lab, Parasite-Host Biology Group, ICMR-National Institute of Malaria Research, New Delhi, India., Pandey KC; Protein Biochemistry and Engineering Lab, Parasite-Host Biology Group, ICMR-National Institute of Malaria Research, New Delhi, India.
Jazyk: angličtina
Zdroj: FEBS open bio [FEBS Open Bio] 2021 Mar; Vol. 11 (3), pp. 578-587. Date of Electronic Publication: 2021 Feb 17.
DOI: 10.1002/2211-5463.13034
Abstrakt: Substrate specificity of an enzyme is an important characteristic of its mechanism of action. Investigation of the nucleotide specificity of Plasmodium falciparum succinyl-CoA synthetase (SCS; PfSCS) would provide crucial insights of its substrate recognition. Charged gatekeeper residues have been shown to alter the substrate specificity via electrostatic interactions with approaching substrates. The enzyme kinetics of recombinant PfSCS (wild-type), generated by refolding of the individual P. falciparum SCSβ and Blastocystis SCSα subunits, demonstrated ADP-forming activity (K mATP  = 48 µm). Further, the introduction of charged gatekeeper residues, either positive (Lys and Lys) or negative (Glu and Asp), resulted in significant reductions in the ATP affinity of PfSCS. It is interesting to note that the recombinant PfSCSβ subunit can be refolded to a functional enzyme conformation using Blastocystis SCSα, indicating the possibility of subunits swapping among different organisms. These results concluded that electrostatic interactions at the gatekeeper region alone are insufficient to alter the substrate specificity of PfSCS, and further structural analysis with a particular focus on binding site architecture is required.
(© 2020 The Authors. FEBS Open Bio published by John Wiley & Sons Ltd on behalf of Federation of European Biochemical Societies.)
Databáze: MEDLINE
Externí odkaz: