title: Crystal structures of an acidic phospholipase A(2) from the venom of Naja Kaouthia.
abstract: 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.
authors.affiliation: National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, People's Republic of China.
authors.forename: Lichuan
authors.initials: L
authors.lastname: Gu
authors.forename: Zhiqing
authors.initials: Z
authors.lastname: Wang
authors.forename: Shiying
authors.initials: S
authors.lastname: Song
authors.forename: Yuyan
authors.initials: Y
authors.lastname: Shu
authors.forename: Zhengjiong
authors.initials: Z
authors.lastname: Lin
mesh_terms: D000818:Animals; D002135:Calcium-Binding Proteins / Q000032:analysis; D003460:Crystallization; D004546:Elapid Venoms / Q000737:chemistry* / Q000201:enzymology*; D017815:Elapidae / Q000502:physiology*; D005088:Exocrine Glands / Q000378:metabolism; D008968:Molecular Conformation; D010741:Phospholipases A / Q000032:analysis*; D013237:Stereoisomerism
chemical_list: D002135:Calcium-Binding Proteins; D004546:Elapid Venoms; D010741:Phospholipases A