title: Isolation, purification, crystallization and preliminary crystallographic studies of amaryllin, a plant pathogenesis-related protein from Amaryllis belladonna.
abstract: A novel antifungal protein, amaryllin, has been isolated from the underground bulbs of Amaryllis belladonna, purified to homogeneity and crystallized. The protein was extracted using ammonium sulfate fractionation. The purified protein samples indicated a molecular weight of 15 kDa on SDS-PAGE. The protein showed antifungal activity against Aspergillus flavus and Fusarium oxysporum. The N-terminal sequence of the first 15 amino-acid residues was determined using Edman degradation and did not show significant sequence identity to any known protein. The protein was crystallized using the hanging-drop vapour-diffusion method with 30% PEG 8000 as precipitating agent. The crystals diffracted to 2.7 A resolution and belonged to the orthorhombic space group I222 or I2(1)2(1)2(1), with unit-cell parameters a = 48.6, b = 61.9, c = 79.6 A. The complete sequence and structure determination of amaryllin are in progress.
authors.affiliation: Department of Biophysics, All India Institute of Medical Sciences, New Delhi 110029, India.
authors.forename: Sanjit
authors.initials: S
authors.lastname: Kumar
authors.forename: Nagendra
authors.initials: N
authors.lastname: Singh
authors.forename: Mau
authors.initials: M
authors.lastname: Sinha
authors.forename: Punit
authors.initials: P
authors.lastname: Kaur
authors.forename: A
authors.initials: A
authors.lastname: Srinivasan
authors.forename: Sujata
authors.initials: S
authors.lastname: Sharma
authors.forename: T P
authors.initials: TP
authors.lastname: Singh
mesh_terms: D000595:Amino Acid Sequence; D000935:Antifungal Agents / Q000494:pharmacology; D001231:Aspergillus flavus / Q000187:drug effects; D001426:Bacterial Proteins / Q000737:chemistry* / Q000302:isolation & purification* / Q000494:pharmacology; D002021:Buffers; D003460:Crystallization; D018360:Crystallography, X-Ray; D003625:Data Collection; D005670:Fusarium / Q000187:drug effects; D006863:Hydrogen-Ion Concentration; D019668:Liliaceae / Q000737:chemistry*; D008826:Microbial Sensitivity Tests; D008969:Molecular Sequence Data; D008970:Molecular Weight; D010710:Phosphates / Q000737:chemistry; D010940:Plant Proteins / Q000737:chemistry* / Q000302:isolation & purification* / Q000494:pharmacology; D013223:Statistics as Topic; D013997:Time Factors; D014961:X-Ray Diffraction
chemical_list: D000935:Antifungal Agents; D001426:Bacterial Proteins; D002021:Buffers; D010710:Phosphates; D010940:Plant Proteins; C541491:amaryllin peptide, Amaryllis belladonna; C053376:pathogenesis-related proteins, plant