1k8t
Crystal structure of the adenylyl cyclase domain of anthrax edema factor (EF)
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OverviewOverview
Oedema factor, a calmodulin-activated adenylyl cyclase, is important in, the pathogenesis of anthrax. Here we report the X-ray structures of oedema, factor with and without bound calmodulin. Oedema factor shares no, significant structural homology with mammalian adenylyl cyclases or other, proteins. In the active site, 3'-deoxy-ATP and a single metal ion are well, positioned for catalysis with histidine 351 as the catalytic base. This, mechanism differs from the mechanism of two-metal-ion catalysis proposed, for mammalian adenylyl cyclases. Four discrete regions of oedema factor, form a surface that recognizes an extended conformation of calmodulin, which is very different from the collapsed conformation observed in other, structures of calmodulin bound to effector peptides. On calmodulin, binding, an oedema factor helical domain of relative molecular mass 15,000, undergoes a 15 A translation and a 30 degrees rotation away from the, oedema factor catalytic core, which stabilizes a disordered loop and leads, to enzyme activation. These allosteric changes provide the first molecular, details of how calmodulin modulates one of its targets.
About this StructureAbout this Structure
1K8T is a Single protein structure of sequence from Bacillus anthracis with SO4 and NI as ligands. The following page contains interesting information on the relation of 1K8T with [Anthrax Toxin]. Active as Adenylate cyclase, with EC number 4.6.1.1 Full crystallographic information is available from OCA.
ReferenceReference
Structural basis for the activation of anthrax adenylyl cyclase exotoxin by calmodulin., Drum CL, Yan SZ, Bard J, Shen YQ, Lu D, Soelaiman S, Grabarek Z, Bohm A, Tang WJ, Nature. 2002 Jan 24;415(6870):396-402. PMID:11807546
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