title: The use of ACORN in solving a 39.5 kDa macromolecule with 1.9 A resolution laboratory source data.
abstract: Data from the alkaline cellulase apo form were collected at a resolution of 1.9 A using an in-house X-ray source (Cu K alpha). By using different fragments of helices from the model solved by macromolecular crystallographic means, the direct-methods program ACORN was used to arrive at the complete model. Attempts have been made to use various percentages of input phasing information from these helices. The minimum input phasing required in feeding the fragments was about 14% of the whole structure. The phases obtained from ACORN were of superb quality, allowing automated model building to be carried out using ARP/wARP. Minimal manual model building was required and the structure determination was completed using the maximum-likelihood refinement program REFMAC. The whole process, starting from the running of ACORN and ending with the refined model, took nearly 15 h of CPU time using a Pentium III PC.
authors.affiliation: Department of Crystallography and Biophysics, University of Madras, Guindy Campus, Chennai 600 025, India.
authors.forename: V
authors.initials: V
authors.lastname: Rajakannan
authors.forename: S
authors.initials: S
authors.lastname: Selvanayagam
authors.forename: T
authors.initials: T
authors.lastname: Yamane
authors.forename: T
authors.initials: T
authors.lastname: Shirai
authors.forename: T
authors.initials: T
authors.lastname: Kobayashi
authors.forename: S
authors.initials: S
authors.lastname: Ito
authors.forename: D
authors.initials: D
authors.lastname: Velmurugan
mesh_terms: D000465:Algorithms; D002480:Cellulase / Q000032:analysis* / Q000737:chemistry*; D003198:Computer Simulation; D046911:Macromolecular Substances; D008958:Models, Molecular; D008970:Molecular Weight; D011487:Protein Conformation; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012984:Software; D014961:X-Ray Diffraction / Q000379:methods*
chemical_list: D046911:Macromolecular Substances; D002480:Cellulase