title: Solving serpin crystal structures.
abstract: Essentially the same steps are required to solve the crystal structure of a serpin as for any other protein: produce and purify protein, grow crystals, collect diffraction data, find estimates of the phase angles, and then refine and validate the structure. For the phasing step, experimental phasing methods involving heavy atom soaks were required for the first few structures, but with the large number of serpin structures now available, molecular replacement has become the method of choice. Two things are special about serpins. First, because of the central role of conformational change in serpin mechanism, it is advisable to consider a variety of molecular replacement models in different conformations and then to allow for rigid-body motions in the initial refinement steps. Second, probably owing to the flexibility of serpins, the average serpin crystal is significantly less well ordered than the average crystal of another protein, which increases the difficulty of solving and refining their structures.
authors.affiliation: Department of Haematology, Cambridge Institute for Medical Research, University of Cambridge, Cambridge, United Kingdom.
authors.forename: Randy J
authors.initials: RJ
authors.lastname: Read
authors.forename: Aiwu
authors.initials: A
authors.lastname: Zhou
authors.forename: Penelope E
authors.initials: PE
authors.lastname: Stein
mesh_terms: D000818:Animals; D016466:CHO Cells; D006224:Cricetinae; D003460:Crystallization / Q000379:methods*; D018360:Crystallography, X-Ray / Q000379:methods*; D004926:Escherichia coli; D006031:Glycosylation; D006801:Humans; D008958:Models, Molecular; D008967:Molecular Biology / Q000379:methods*; D017395:Plasminogen Activator Inhibitor 1 / Q000096:biosynthesis / Q000235:genetics / Q000302:isolation & purification*; D017510:Protein Folding; D017433:Protein Structure, Secondary; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis / Q000235:genetics / Q000302:isolation & purification*; D015843:Serpins / Q000096:biosynthesis / Q000235:genetics / Q000302:isolation & purification*; D000515:alpha 1-Antitrypsin / Q000096:biosynthesis / Q000235:genetics / Q000302:isolation & purification*
chemical_list: D017395:Plasminogen Activator Inhibitor 1; D011993:Recombinant Fusion Proteins; C085344:SERPIN-B5; C051321:SERPINE1 protein, human; D015843:Serpins; D000515:alpha 1-Antitrypsin