title: Ab initio phasing of a 4189-atom protein structure at 1.2 A resolution.
abstract: The phase problem remains a key rate-limiting step in the determination of macromolecular X-ray structures. Direct methods, applying probability theory to the native data set, can routinely solve structures of up to about 200 non-H atoms, although much larger structures have been solved given sufficiently high resolution data and the presence of heavy atoms. Here it is shown that maximum-likelihood refinement of free-atom models with ARP/wARP can solve ab initio a much larger metalloprotein structure than the largest so far solved by conventional direct methods. The protein, OppA, is not naturally associated with metal ions but was co-crystallized with uranium.
authors.affiliation: Protonic Nanomachine Project, ERATO, Kyoto 619-0237, Japan. jtame@npn.jst.go.jp
authors.forename: J R
authors.initials: JR
authors.lastname: Tame
mesh_terms: D001426:Bacterial Proteins; D002352:Carrier Proteins / Q000737:chemistry*; D018360:Crystallography, X-Ray; D008074:Lipoproteins / Q000737:chemistry*; D008667:Metalloproteins / Q000737:chemistry; D008958:Models, Molecular; D010363:Pattern Recognition, Automated; D011487:Protein Conformation; D012984:Software; D014501:Uranium / Q000737:chemistry
chemical_list: D001426:Bacterial Proteins; D002352:Carrier Proteins; D008074:Lipoproteins; D008667:Metalloproteins; C046506:oligopeptide-binding protein, bacteria; D014501:Uranium