title: Fast and automatic identification of particle tilt pairs based on Delaunay triangulation.
abstract: Random conical tilt (RCT) and orthogonal tilt reconstruction (OTR) are two remarkable methods for reconstructing the three-dimensional structure of macromolecules at low resolution. These techniques use two images at two different sample tilts. One of the most demanding steps in these methods at the image processing level is to identify corresponding particles on both micrographs, and manual or semiautomatic matching methods are usually used. Here we present an approach to solve this bottleneck with a fully automatic method for assigning particle tilt pairs. This new algorithm behaves correctly with a variety of samples, covering the range from small to large macromolecules and from sparse to densely populated fields of view. It is also more rapid than previous approaches. The roots of the method lie in a Delaunay triangulation of the set of independently picked coordinates on both the untilted and tilted micrographs. These triangulations are then used to search an affine transformation between the untilted and tilted triangles. The affine transformation that maximizes the number of correspondences between the two micrographs defines the coordinate matching.
authors: Biocomputing Unit, Centro Nacional de Biotectnologíay (CNB-CSIC), Darwin, 3, Campus Universidad Autónoma, 28049 Cantoblanco, Madrid, Spain. Electronic address: jlvilas@cnb.csic.es.
authors: J L
authors: JL
authors: Vilas
authors: Biocomputing Unit, Centro Nacional de Biotectnologíay (CNB-CSIC), Darwin, 3, Campus Universidad Autónoma, 28049 Cantoblanco, Madrid, Spain.
authors: J
authors: J
authors: Navas
authors: Biocomputing Unit, Centro Nacional de Biotectnologíay (CNB-CSIC), Darwin, 3, Campus Universidad Autónoma, 28049 Cantoblanco, Madrid, Spain.
authors: J
authors: J
authors: Gómez-Blanco
authors: Biocomputing Unit, Centro Nacional de Biotectnologíay (CNB-CSIC), Darwin, 3, Campus Universidad Autónoma, 28049 Cantoblanco, Madrid, Spain.
authors: J M
authors: JM
authors: de la Rosa-Trevín
authors: Biocomputing Unit, Centro Nacional de Biotectnologíay (CNB-CSIC), Darwin, 3, Campus Universidad Autónoma, 28049 Cantoblanco, Madrid, Spain.
authors: R
authors: R
authors: Melero
authors: GSK Vaccine, Via Fiorentina 1, Siena, Italy.
authors: I
authors: I
authors: Peschiera
authors: GSK Vaccine, Via Fiorentina 1, Siena, Italy.
authors: I
authors: I
authors: Ferlenghi
authors: Biocomputing Unit, Centro Nacional de Biotectnologíay (CNB-CSIC), Darwin, 3, Campus Universidad Autónoma, 28049 Cantoblanco, Madrid, Spain.
authors: J
authors: J
authors: Cuenca
authors: Escuela Politécnica Superior, Universidad Autónoma de Madrid, Campus Universidad Autónoma, 28049 Cantoblanco, Madrid, Spain.
authors: R
authors: R
authors: Marabini
authors: Biocomputing Unit, Centro Nacional de Biotectnologíay (CNB-CSIC), Darwin, 3, Campus Universidad Autónoma, 28049 Cantoblanco, Madrid, Spain.
authors: J M
authors: JM
authors: Carazo
authors: Biocomputing Unit, Centro Nacional de Biotectnologíay (CNB-CSIC), Darwin, 3, Campus Universidad Autónoma, 28049 Cantoblanco, Madrid, Spain; Bioengineering Lab, Escuela Politécnica Superior, Universidad San Pablo CEU, Campus Urb. Montepríncipe s/n, 28668, Boadilla del Monte, Madrid, Spain.
authors: J
authors: J
authors: Vargas
authors: Biocomputing Unit, Centro Nacional de Biotectnologíay (CNB-CSIC), Darwin, 3, Campus Universidad Autónoma, 28049 Cantoblanco, Madrid, Spain; Bioengineering Lab, Escuela Politécnica Superior, Universidad San Pablo CEU, Campus Urb. Montepríncipe s/n, 28668, Boadilla del Monte, Madrid, Spain. Electronic address: coss@cnb.csic.es.
authors: C O S
authors: COS
authors: Sorzano
mesh_terms: D000465:Algorithms; D020285:Cryoelectron Microscopy / Q000379:methods; D021621:Imaging, Three-Dimensional / Q000379:methods*; D046911:Macromolecular Substances / Q000737:chemistry* / Q000648:ultrastructure
chemical_list: D046911:Macromolecular Substances
keywords: Automatic picking; Electron microscopy; Orthogonal tilt; Random conical tilt; Single Particle Analysis