Crystal structures of an acidic phospholipase A(2) from the venom of Naja Kaouthia

• Published in: Toxicon (Oxford) Vol. 40; no. 7; pp. 917 - 922
• Main Authors: Gu, Lichuan, Wang, Zhiqing, Song, Shiying, Shu, Yuyan, Lin, Zhengjiong
• Format: Journal Article
• Language: English
• Published: England 01.07.2002
• Subjects: Animals; Calcium-Binding Proteins - analysis; Crystallization; Elapid Venoms - chemistry; Elapid Venoms - enzymology; Elapidae - physiology; Exocrine Glands - metabolism; Molecular Conformation; Phospholipases A - analysis; Stereoisomerism
• ISSN: 0041-0101
• DOI: 10.1016/S0041-0101(02)00085-5

A phospholipase A(2) purified from the venom of Naja kaouthia (Guangxi cobra) exhibits anticoagulant activities. The structures of two crystal forms were determined by X-ray crystallography at 2.8A resolution with the Naja naja (India cobra) PLA(2) as an initial model. The enzyme exhibits a trimer structure, which is similar to that of India cobra PLA(2). This reinforces the physiological relevance of the oligomer. The trimer has a wide cavity, which allows the substrate to enter and interact with the catalytic site. The formation of the trimer may serve as a storage method to improve the solubility at high concentration in the venom gland. The Ca2+ binding loop in the absence of the cation can exist in different conformations depending on its surroundings.