title: Crystallization of restriction endonuclease SfiI in complex with DNA.
abstract: The SfiI endonuclease from Streptomyces fimbriatus (EC 3.1.21.4) is a tetrameric enzyme that binds simultaneously to two recognition sites and cleaves both sites concertedly. It serves as a good model system for studying both specificity and cooperative DNA binding. Crystals of the enzyme were obtained by the hanging-drop vapor-diffusion method in complex with a 21-mer oligonucleotide. The crystals are trigonal, with unit-cell parameters a = b = 85.7, c = 202.6 A, and diffract to 2.6 A resolution on a rotating-anode X-ray generator. Preliminary X-ray analysis reveals the space group to be either P3(1)21 or P3(2)21. Interestingly, the crystals change to space group P6(1)22, with unit-cell parameters a = b = 85.5, c = 419.6 A, when the selenomethionyl (SeMet) derivative of the enzyme is co-crystallized with the same DNA. Phase information is currently being derived from this SeMet SfiI-DNA complex.
authors.affiliation: Department of Physiology and Biophysics, Mount Sinai School of Medicine, New York, NY 10029, USA.
authors.forename: Hector
authors.initials: H
authors.lastname: Viadiu
authors.forename: Eva Scheuring
authors.initials: ES
authors.lastname: Vanamee
authors.forename: Eric M
authors.initials: EM
authors.lastname: Jacobson
authors.forename: Ira
authors.initials: I
authors.lastname: Schildkraut
authors.forename: Aneel K
authors.initials: AK
authors.lastname: Aggarwal
mesh_terms: D003460:Crystallization; D018360:Crystallography, X-Ray; D004247:DNA / Q000737:chemistry; D015252:Deoxyribonucleases, Type II Site-Specific / Q000737:chemistry*; D009841:Oligonucleotides / Q000737:chemistry; D011485:Protein Binding; D013302:Streptomyces / Q000201:enzymology; D014965:X-Rays
chemical_list: D009841:Oligonucleotides; D004247:DNA; C041749:endodeoxyribonuclease SfiI; D015252:Deoxyribonucleases, Type II Site-Specific