title: Purification, N-terminal sequencing, crystallization and preliminary X-ray diffraction analysis of atratoxin, a new short-chain alpha-neurotoxin from the venom of Naja naja atra.
abstract: Atratoxin, a new alpha-neurotoxin purified to homogeneity by a series of liquid chromatographies from the venom of Naja naja atra (mainland Chinese cobra), is a small single-polypeptide alkaline protein with a pI of about 9.5 and molecular weight of 6952 Da estimated by mass spectrometry. Although the sequencing of the N-terminal 15 residues (LECHNQQTTQQPEGG) shows that this neurotoxic protein contains most of the residues, especially at the conserved positions, of the consensus sequence of short-chain alpha-neurotoxins, the natural mutations in the N-terminal Loop-1 presented by the sequence alignment may have structural or functional implications for the interactions between alpha-neurotoxins and related receptors. Single crystals of atratoxin have been grown from drops containing the necessary Cu(2+) ions by the conventional hanging-drop vapour-diffusion method. The crystals diffract X-rays to 1.6 A resolution and belong to space group C222(1), with unit-cell parameters a = 47.36, b = 47.83, c = 91.31 A, corresponding to a volume-to-mass ratio of 1.85 A(3) Da(-1) and two molecules in each asymmetric unit.
authors.affiliation: Key Laboratory of Structural Biology, University of Science and Technology of China, CAS, 96 Jinzhai Road, Hefei, Anhui 230026, People's Republic of China.
authors.forename: Xiongying
authors.initials: X
authors.lastname: Tu
authors.forename: Qingqiu
authors.initials: Q
authors.lastname: Huang
authors.forename: Xiaohua
authors.initials: X
authors.lastname: Lou
authors.forename: Maikun
authors.initials: M
authors.lastname: Teng
authors.forename: Liwen
authors.initials: L
authors.lastname: Niu
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002850:Chromatography, Gel; D002851:Chromatography, High Pressure Liquid; D003460:Crystallization; D004546:Elapid Venoms / Q000737:chemistry*; D017815:Elapidae; D007526:Isoelectric Point; D013058:Mass Spectrometry; D008970:Molecular Weight; D009498:Neurotoxins / Q000737:chemistry* / Q000302:isolation & purification*; D020539:Sequence Analysis, Protein; D014961:X-Ray Diffraction
chemical_list: D004546:Elapid Venoms; D009498:Neurotoxins