110 likes | 298 Views
Structural Analysis of Maize Streak Virus Single and Geminate Particles. Robbie Reutzel University of Florida Molecular Structure Group. MSV Introduction:. Member of mastreviruses Transmitted by leafhoppers Monopartite ssDNA genome (~2.7kb)
E N D
Structural Analysis of Maize Streak Virus Single and Geminate Particles Robbie Reutzel University of Florida Molecular Structure Group
MSV Introduction: Member of mastreviruses Transmitted by leafhoppers Monopartite ssDNA genome (~2.7kb) Geminate particle consists of 110 copies of 28kDa coat protein Single, isometric (T=1) particles also found MSV infected leaf Leafhopper, Cicadulina mbila
Geminate Model Evolution Based on STNV (1984) Negative Stain EM 25Å (Zhang et al., 2001) Ping-Pong Model (1979) 12Å (Jan. 2005)
MSV Geminate Particle Refinement: Assuming 52 point group
CTF Correction Not able to collect SAXS (small angle x-ray scattering) data Used “bootstrapping” technique outlined in the EMAN FAQ Micrographs from 1.0-3.6 defocus were used
Geminate Particle: Latest Model 9.0Å Resolution
MSV Single Particle Model What is the difference between the capsomers? How are these particles related to the assembly mechanism? 10.2Å Resolution
Homology Modelling and Manual Fitting MSV coat protein shares ~20% homology with STNV Capsid models built and fitted manually using O
Proposed Assembly of MSV Capsids Phosphorylation Sulfation Glycosylation Truncation Geminate Capsid Single Capsid ? 1 N 1 Infectious 3 Dead End? ? 3 2 Pentameric Capsomers 2 + + ? ssDNA sg ssDNA
Unanswered Questions What are the connections along the geminate particle equator? What are the differences in coat protein conformation between single and geminate particles? Very interested in using Helix and Foldhunter
Acknowledgements University of Florida: Dr. Robert McKenna Dr. Mavis Agbandje-McKenna Antonette Bennett G. Javier Ortiz Eric Padron David Rodriguez Purdue University/UCSD: Dr. Tim Baker Dr. Valorie Bowman Paul Chipman Dr. Norman H. Olson Dr. Wei Zhang Xing Zhang Xiaodong Yan John Innes Centre: Dr. Margaret Boulton Samantha Bean