Enhancement of Phospholipid Binding and Catalytic
Efficiency of Streptomyces klenkii Phospholipase
D by Increasing Hydrophobicity of the Active Site Loop
posted on 2021-09-13, 19:17authored byRongkang Hu, Ruiguo Cui, Qingyun Tang, Dongming Lan, Fanghua Wang, Yonghua Wang
The mechanism of active site loops
of Streptomyces phospholipase D (PLD)
binding to the lipid–water interface
for catalytic reactions still remains elusive. A flexible loop (residues
376–382) in the active site of Streptomyces
klenkii PLD (SkPLD) is conserved within PLDs in most
of the Streptomyces species. The residue
Ser380 was found to be essential for the enzyme’s adsorption
to the interface and its substrate recognition. The S380V mutant showed
a 4.8 times higher catalytic efficiency and nearly seven times higher
adsorption equilibrium coefficient compared to the wild-type SkPLD.
The monolayer film technique has confirmed that the substitution of
Ser380 with valine in the loop exhibited positive interaction between
the enzyme and PCs with different acyl chain lengths. The results
of the interfacial binding properties indicated that the S380V mutant
might display suitable phosphatidylserine synthesis activity. The
present study will be helpful to explain the role of residue 380 in
the active site loops of Streptomyces PLD.