Korea Research Institute of Bioscience and Biotechnology, Yuseong-gu, Daejeon, Republic of Korea.
Appl Environ Microbiol. 2012 Jul;78(14):4959-66. doi: 10.1128/AEM.00260-12. Epub 2012 Apr 27.
A novel lipolytic enzyme was isolated from a metagenomic library obtained from tidal flat sediments on the Korean west coast. Its putative functional domain, designated MPlaG, showed the highest similarity to phospholipase A from Grimontia hollisae CIP 101886, though it was screened from an emulsified tricaprylin plate. Phylogenetic analysis showed that MPlaG is far from family I.6 lipases, including Staphylococcus hyicus lipase, a unique lipase which can hydrolyze phospholipids, and is more evolutionarily related to the bacterial phospholipase A(1) family. The specific activities of MPlaG against olive oil and phosphatidylcholine were determined to be 2,957 ± 144 and 1,735 ± 147 U mg(-1), respectively, which means that MPlaG is a lipid-preferred phospholipase. Among different synthetic esters, triglycerides, and phosphatidylcholine, purified MPlaG exhibited the highest activity toward p-nitrophenyl palmitate (C(16)), tributyrin (C(4)), and 1,2-dihexanoyl-phosphatidylcholine (C(8)). Finally, MPlaG was identified as a phospholipase A(1) with lipase activity by cleavage of the sn-1 position of OPPC, interfacial activity, and triolein hydrolysis. These findings suggest that MPlaG is the first experimentally characterized phospholipase A(1) with lipase activity obtained from a metagenomic library. Our study provides an opportunity to improve our insight into the evolution of lipases and phospholipases.
从韩国西海岸潮间带沉积物的宏基因组文库中分离到一种新型脂肪酶。其假定的功能域，命名为 MPlaG，与 Grimontia hollisae CIP 101886 的磷脂酶 A 具有最高的相似性，尽管它是从乳化三辛酸甘油酯平板中筛选出来的。系统发育分析表明，MPlaG 远离 I.6 家族的脂肪酶，包括可水解磷脂的猪葡萄球菌脂肪酶，它是一种独特的脂肪酶，与细菌磷脂酶 A(1)家族的关系更为密切。MPlaG 对橄榄油和磷脂酰胆碱的比活性分别为 2957±144 和 1735±147 U mg(-1)，这意味着 MPlaG 是一种脂肪偏好性的磷脂酶。在不同的合成酯、甘油三酯和磷脂酰胆碱中，纯化的 MPlaG 对 p-硝基苯棕榈酸酯 (C(16))、三丁酸甘油酯 (C(4)) 和 1,2-二己酰基磷脂酰胆碱 (C(8)) 的活性最高。最后，通过 OPPC 的 sn-1 位切割、界面活性和三油精水解，确定 MPlaG 为具有脂肪酶活性的磷脂酶 A(1)。这些发现表明，MPlaG 是从宏基因组文库中获得的第一个具有实验特征的具有脂肪酶活性的磷脂酶 A(1)。我们的研究为深入了解脂肪酶和磷脂酶的进化提供了机会。
