title: Crystallization and preliminary X-ray study of the edema factor exotoxin adenylyl cyclase domain from Bacillus anthracis in the presence of its activator, calmodulin.
abstract: Edema factor from Bacillus anthracis is a 92 kDa secreted adenylyl cyclase exotoxin and is activated by the host-resident protein calmodulin. Calmodulin is a ubiquitous intracellular calcium sensor in eukaryotes and activates edema factor nearly 1000-fold upon binding. While calmodulin has many known effectors, including kinases, phosphodiesterases, motor proteins, channels and type 1 adenylyl cyclases, no structures of calmodulin in complex with a functional enzyme have been solved. The crystallization and initial experimental phasing of crystals containing a complex of edema factor adenylyl cyclase domain and calmodulin are reported here. The edema factor-calmodulin complex crystallizes in three different space groups. A native data set in the I222 space group has been collected to 2.7 A and the self-rotation function solution suggests three edema factor-calmodulin complexes in each asymmetric unit. Initial 4 A phases were obtained by selenomethionyl MAD in combination with two heavy-atom derivatives. These phases were successfully extended to 2.7 A using NCS averaging.
authors.affiliation: Committee on Neurobiology, The University of Chicago, 924 East 57th Street, Chicago, IL 60637, USA.
authors.forename: C L
authors.initials: CL
authors.lastname: Drum
authors.forename: Y
authors.initials: Y
authors.lastname: Shen
authors.forename: P A
authors.initials: PA
authors.lastname: Rice
authors.forename: A
authors.initials: A
authors.lastname: Bohm
authors.forename: W J
authors.initials: WJ
authors.lastname: Tang
mesh_terms: D000262:Adenylyl Cyclases / Q000737:chemistry* / Q000378:metabolism; D000942:Antigens, Bacterial; D001408:Bacillus anthracis / Q000737:chemistry* / Q000201:enzymology; D001427:Bacterial Toxins; D002147:Calmodulin / Q000737:chemistry*; D003460:Crystallization; D018360:Crystallography, X-Ray; D008958:Models, Molecular; D011487:Protein Conformation
chemical_list: D000942:Antigens, Bacterial; D001427:Bacterial Toxins; D002147:Calmodulin; C030325:anthrax toxin; D000262:Adenylyl Cyclases