Detecting asymmetry in the presence of symmetry with maximum likelihood three-dimensional reconstructions of viruses from electron microscope images

• Published in: IET image processing Vol. 10; no. 8; pp. 624 - 629
• Main Authors: Wang, Kang, Fu, Chi-yu, Catalano, Carlos E, Prevelige, Peter E, Doerschuk, Peter C, Johnson, John E
• Format: Journal Article
• Language: English
• Published: The Institution of Engineering and Technology 01.08.2016
• Subjects: 3D maximum likelihood reconstruction; Algorithms; Asymmetry; bacteriophage Lambda procapsid data; biological techniques; computed electron tomography; computerised tomography; cryogenics; electron microscope images; Image processing; microorganisms; nanometre scale biological machines; Nanostructure; Probability density functions; Reconstruction; ribosomes; single particle cryoelectron microscopy; Transmission electron microscopy; Viruses; viruses; bacteriophage Lambda procapsid data; cryogenics; 3D maximum likelihood reconstruction; asymmetry; probability density functions; ribosomes; computerised tomography; single particle cryoelectron microscopy; nanometre scale biological machines; microorganisms; electron microscope images; biological techniques; transmission electron microscopy; computed electron tomography
• ISSN: 1751-9659; 1751-9667; 1751-9667
• DOI: 10.1049/iet-ipr.2015.0737

Various modes of transmission electron microscopy can provide unique structural information on nanometre-scale biological machines such as viruses and ribosomes. A maximum-likelihood statistical reconstruction algorithm using information from two such modalities, single-particle cryo-electron microscopy and computed electron tomography, is described for the problem where the machine is nearly symmetrical, but the localised regions of asymmetry are important for the functioning of the machine. The algorithm is demonstrated on experimental bacteriophage Lambda procapsid data. Key features of the algorithm are the use of probability density functions (pdfs) derived from normalised correlation rather than Gaussian pdfs and the solution of a constrained classification problem in which 11 out of 12 sites of asymmetry belong to one class while the 12th site belongs to a second class.