Strategies for 3D reconstruction of macromolecules existing as single particles

The aim of the "single-particle" image processing with SPIDER is to obtain a 3D reconstruction of a macromolecule from a large set of particle images (that are obtained with the electron microscope), based on the premise that each of these particle images shows the same structure. Since the macromolecule is single, without a structural context that would stabilize its orientation, it occurs in many different orientations. Thus, the electron micrograph normally displays a wide range of particle views. But it is unknown, in the absence of prior knowledge, how these views are related to one another. Thus the 3D reconstruction procedure must deal with two separate issues:

The following is a guide on how to proceed, using established methods of orientation search and 3D reconstruction.

Let's say the structure is entirely unknown. In that case, you have to start from scratch:

-- or - However if the structure is already available from a previous reconstruction, albeit at low resolution, you can use the existing template in the following way:
Source: strategies.html     Last update: 3 Mar. 1999    
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