부산대학교 도서관

Bucain is a three-linger toxin, structurally homologous to snakevenom muscarinic toxins, from the venom of the Malayan krait Bungarus candidus. These proteins have molecular masses of approximately 6000-8000 Da and encompass the potent curaremimetic neurotoxins which confer lethality to Elapidae and Hydrophidae venoms. Bucain was crystallized in two crystal forms by the hanging-drop vapour-diffusion technique in 0.1 M sodium citrate pH 5.6, 15% PEG 4000 and 0.15 M ammonium acetate. Form I crystals belong to the monoclinic system space group C2, with unitcell parameters a = 93.73, b = 49.02, c = 74.09 Å, β = 111.32°, and diffract to a nominal resolution of 1.61 Å. Form II crystals also belong to the space group C2, with unit-cell parameters a = 165.04, b = 49.44, c = 127.60 Å, β = 125.55°, and diffract to a nominal resolution of 2.78 Å. The self-rotation function indicates the presence of four and eight molecules in the crystallographic asymmetric unit of the form I and form II crystals, respectively. Attempts to solve these structures by molecular-replacement methods have not been successful and a heavy-atom derivative search has been initiated. [ABSTRACT FROM AUTHOR]