title: Applications of ACORN to data at 1.45 A resolution.
abstract: One of the main interests in the molecular biosciences is in understanding structure-function relations and X-ray crystallography plays a major role in this. ACORN can be used as a comprehensive and efficient phasing procedure for the determination of protein structures when atomic resolution data are available. An initial model can automatically be built by ARP/wARP followed by REFMAC for refinement. The alpha helices and beta sheets occurring in many protein structures can be taken as starting fragments for structure solution in ACORN. ACORN, along with ARP/wARP followed by REFMAC, can be an ab initio method for solving protein structure for which data are better than 1.2 A (atomic resolution). Attempts are here made in extending its applications to real data at 1.45 A resolution and also to truncated data at 1.6 A resolution. Two previously known structures, congerin II and alkaline cellulase N257, were resolved using the above approach. Automatic structure solution, phasing and refinement for real data at still lower resolutions for proteins of various complexities are being carried out. Data mining of the secondary structural features using PDB is being carried out for this new approach for 'seed-phasing' to ACORN.
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: 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; D044602:Cellulases / Q000737:chemistry; D018360:Crystallography, X-Ray / Q000379:methods*; D003628:Database Management Systems; D030562:Databases, Protein; D037161:Galectins / Q000737:chemistry; D008958:Models, Molecular; D011487:Protein Conformation; D017433:Protein Structure, Secondary; D011506:Proteins / Q000737:chemistry*; D011786:Quality Control; D012680:Sensitivity and Specificity; D020539:Sequence Analysis, Protein / Q000379:methods*; D012984:Software
chemical_list: D037161:Galectins; D011506:Proteins; C122080:congerin II protein, Conger eel; D044602:Cellulases