Structural Biochemistry & Molecular Biophysics Laboratory, Department of Biochemistry, College of Life Science and Biotechnology, Yonsei University, Seoul 03722, Korea.
PCG-Biotech, Ltd., 508 KBIZ DMC Tower, Sangam-ro, Seoul 03929, Korea.
Molecules. 2022 Apr 2;27(7):2317. doi: 10.3390/molecules27072317.
Phospholipase is an enzyme that hydrolyzes various phospholipid substrates at specific ester bonds and plays important roles such as membrane remodeling, as digestive enzymes, and the regulation of cellular mechanism. Phospholipase proteins are divided into following the four major groups according to the ester bonds they cleave off: phospholipase A1 (PLA1), phospholipase A2 (PLA2), phospholipase C (PLC), and phospholipase D (PLD). Among the four phospholipase groups, PLA1 has been less studied than the other phospholipases. Here, we report the first molecular structures of plant PLA1s: AtDSEL and CaPLA1 derived from and , respectively. AtDSEL and CaPLA1 are novel PLA1s in that they form homodimers since PLAs are generally in the form of a monomer. The dimerization domain at the C-terminal of the AtDSEL and CaPLA1 makes hydrophobic interactions between each monomer, respectively. The C-terminal domain is also present in PLA1s of other plants, but not in PLAs of mammals and fungi. An activity assay of AtDSEL toward various lipid substrates demonstrates that AtDSEL is specialized for the cleavage of -1 acyl chains. This report reveals a new domain that exists only in plant PLA1s and suggests that the domain is essential for homodimerization.
磷脂酶是一种能够在特定酯键处水解各种磷脂质底物的酶，在膜重塑、消化酶以及细胞机制调控等方面发挥着重要作用。根据它们切断的酯键，磷脂酶蛋白可分为以下四大类：磷脂酶 A1（PLA1）、磷脂酶 A2（PLA2）、磷脂酶 C（PLC）和磷脂酶 D（PLD）。在这四类磷脂酶中，PLA1 比其他磷脂酶研究得更少。在这里，我们报告了植物 PLA1 分子结构的首例：分别来自 和 的 AtDSEL 和 CaPLA1。AtDSEL 和 CaPLA1 是新型 PLA1，因为它们形成同源二聚体，而 PLA 通常以单体形式存在。AtDSEL 和 CaPLA1 的 C 末端二聚化结构域分别在单体之间形成疏水相互作用。C 末端结构域也存在于其他植物的 PLA1 中，但不存在于哺乳动物和真菌的 PLA 中。对各种脂质底物的 AtDSEL 活性测定表明，AtDSEL 专门用于切割-1 酰基链。本报告揭示了仅存在于植物 PLA1 中的一个新结构域，并表明该结构域对于同源二聚化至关重要。
