National Resource for Automated Molecular Microscopy

National Resource for Automated Molecular Microscopy

Research Emphasis

The overall mission of the National Resource for Automated Molecular Microscopy is to develop, test, and apply technology aimed toward completely automating the processes involved in solving macromolecular structures using cryoelectron microscopy (cryoEM). The goal is to establish a resource that will serve both as a center for high-throughput molecular microscopy as well as for transferring this technique to the research community.

Core technology development projects include the following:

Specimen handling: Projects in this core are all related to improving the handling and monitoring of specimens by developing innovative new engineering devices. These include developing methods for high throughput screening of negatively stained ordered arrays and controlling the stability of cryostage specimen holders.

Automated acquisition: The fundamental core technology of the resource is the development of a generalized system for automated image acquisition.

Automated processing: The focus of this core is the automation of the data processing that follows image acquisition. A particular emphasis is the automated identification and segmentation of individual structures from electron micrographs.

Information handling: The storage, organization, distribution, and archiving of information is the focus of this core project.

Resource Capabilities

Instrument

Two FEI F20 Tecnai (200 KeV, FEG) transmission electron microscope equipped with a 4K x 4K charge-coupled device (CCD) camera; an FEI CM200 (200 KeV, FEG) equipped with a 2K x 2K Tietz CCD camera; an FEI CM120 (120 KeV, LaB6) with a 2K x 2K Tietz CCD camera and an FEI EM208 (screening). All of the peripheral equipment normally associated with a cryoEM lab is also available. This includes capabilities for making cryospecimens, cryostages, scanners, an optical bench, etc.

Software

The resource distributes several software packages including those listed below:

Leginon: A system designed to automate the collection of images for cryoEM. Several smaller software packages related to microscope control and automation are also available.

ACE: A MATLAB Toolbox for automatically estimating and correcting the contrast transfer function of an image.

Training Opportunities and Workshops

Recurring workshops include a biennial practical training course in cryoEM and regular Leginon training workshops.

Publications

1. Stagg, S. M., Gurkan, C., et al., Structure of the Sec 12/31 COPII coat cage. Nature 439:234–238, 2006.

2. Suloway, C., Pulokas, J., et al., Automated molecular microscopy: The new Leginon system. Journal of Structural Biology 151:41–-60, 2005.

3. Mallick, S. P., Carragher, B., et al., ACE: automated CTF estimation. Ultramicroscopy 104:8–29, 2005.