Dr. Trevor Sewell
Electron Microscope Unit
University of Cape Town
Rondebosch, South Africa

Thursday, March 5, 2009
2:00 pm (CT)
3269 Beckman Institute

Abstract

Obtaining three dimensional reconstructions of macromolecules from images of fields of such molecules taken by either negative stain or cryo microscopy is a tractable problem which in some cases is routine. The maps generated typically have resolutions of 1.5 to 3 nm. Frequently there are homologs to all or part of the molecule of interest available in the Protein Data Bank. There are also frequently symmetry considerations and other information that aid in interpretation of the maps. I will describe our experience in interpreting several such maps including: nitrilases, GroEL E461K, glutamine synthetase type III and the histone octamer, in order to motivate the creation of a program that combines map information, homology modeling, awareness of symmetry and molecular mechanics considerations. I believe that this will improve the quality of the insights that can be obtained from such maps.