Acyl Chain Specificity of Marine Streptomyces klenkii PhosPholipase D and Its Application in Enzymatic Preparation of Phosphatidylserine.

Rongkang Hu,Ruiguo Cui,Dongming Lan,Yonghua Wang,Fanghua Wang

doi:10.3390/ijms221910580

Rongkang Hu, Ruiguo Cui + Show 3 more

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https://doi.org/10.3390/ijms221910580

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Abstract

Mining of phospholipase D (PLD) with altered acyl group recognition except its head group specificity is also useful in terms of specific acyl size phospholipid production and as diagnostic reagents for quantifying specific phospholipid species. Microbial PLDs from Actinomycetes, especially Streptomyces, best fit this process requirements. In the present studies, a new PLD from marine Streptomyces klenkii (SkPLD) was purified and biochemically characterized. The optimal reaction temperature and pH of SkPLD were determined to be 60 °C and 8.0, respectively. Kinetic analysis showed that SkPLD had the relatively high catalytic efficiency toward phosphatidylcholines (PCs) with medium acyl chain length, especially 12:0/12:0-PC (67.13 S−1 mM−1), but lower catalytic efficiency toward PCs with long acyl chain (>16 fatty acids). Molecular docking results indicated that the different catalytic efficiency was related to the increased steric hindrance of long acyl-chains in the substrate-binding pockets and differences in hydrogen-bond interactions between the acyl chains and substrate-binding pockets. The enzyme displayed suitable transphosphatidylation activity and the reaction process showed 26.18% yield with L-serine and soybean PC as substrates. Present study not only enriched the PLD enzyme library but also provide guidance for the further mining of PLDs with special phospholipids recognition properties.

Highlights

Accepted: 18 September 2021Phospholipids (PLs) are one kinds of mixed lipids containing phosphoric acid, which are the basic component of cell membrane and the essential substance of life [1]
All known Streptomyces phospholipase D (PLD), except the S. chromofuscus PLD, contain two strictly conserved HKD motifs (HXK(X)4 D(X)6 GG/S), which are assumed to act as active center [15]
SkPLD showed substantially high identity to PLD protein sequences from Streptomyces (>70%) (Figures 1 and S2)

Summary

Introduction

Accepted: 18 September 2021Phospholipids (PLs) are one kinds of mixed lipids containing phosphoric acid, which are the basic component of cell membrane and the essential substance of life [1]. PLs have been broadly applied in emulsifiers, components of cosmetics, medical formulations and for liposome preparations because of their unique chemical structure and healthcare functions [2]. Due to the increasing cost of healthcare-related products and expanding health benefits of functional lipids, there is increasing interest in PLs with varying molecular properties (such as charge, polarity, size, etc.) to obtain special functional. Enzymatic modification of natural PLs has become an important way to realize the high value utilization of PLs. PLs consist of a glycerol backbone and a polar head group located at the sn-3 position of the glycerol backbone. Phospholipase D (PLD, EC 3.1.4.4) hydrolyze the phosphodiester bond between phosphate at the sn-3 position of PL and the polar head groups. PLDcatalyzed transphosphatidylation is especially useful in synthesis of naturally less abundant

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