structural analysis of maize streak virus single and geminate particles robbie reutzel university of...
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Structural Analysis of Structural Analysis of Maize Streak Virus Maize Streak Virus
Single and Geminate Single and Geminate ParticlesParticles
Structural Analysis of Structural Analysis of Maize Streak Virus Maize Streak Virus
Single and Geminate Single and Geminate ParticlesParticles
Robbie ReutzelUniversity of Florida
Molecular Structure Group
Robbie ReutzelUniversity of Florida
Molecular Structure Group
MSV Introduction:MSV Introduction:MSV Introduction:MSV Introduction:
Member of mastrevirusesTransmitted by leafhoppersMonopartite ssDNA genome (~2.7kb)Geminate particle consists of 110 copies of 28kDa coat proteinSingle, isometric (T=1) particles also found
Member of mastrevirusesTransmitted by leafhoppersMonopartite ssDNA genome (~2.7kb)Geminate particle consists of 110 copies of 28kDa coat proteinSingle, isometric (T=1) particles also found
MSV infected leaf Leafhopper, Cicadulina mbila
Geminate Model Geminate Model EvolutionEvolutionGeminate Model Geminate Model EvolutionEvolution
Negative Stain EM
Ping-Pong Model (1979)
Based on STNV (1984)
25Å (Zhang et al., 2001)
12Å (Jan.
2005)
MSV Geminate Particle MSV Geminate Particle Refinement:Refinement:MSV Geminate Particle MSV Geminate Particle Refinement:Refinement:
Assuming 52 point group
CTF CorrectionCTF CorrectionCTF CorrectionCTF 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
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: Geminate Particle: Latest ModelLatest Model
Geminate Particle: Geminate Particle: Latest ModelLatest Model
9.0Å Resolution
MSV Single Particle MSV Single Particle ModelModelMSV Single Particle MSV Single Particle ModelModel
What is the difference between the capsomers?
How are these particles related to the assembly mechanism?
10.2Å Resolution
Homology Modelling Homology Modelling and Manual Fittingand Manual Fitting
Homology Modelling Homology Modelling and Manual Fittingand Manual Fitting
MSV coat protein shares ~20% homology with STNV
Capsid models built and fitted manually using O
N
Geminate Capsid
ssDNA
Single Capsid
+
sg ssDNA
+
1
3
3
Proposed Assembly of MSV CapsidsProposed Assembly of MSV Capsids
2
1?
?
?
Phosphorylation Sulfation Glycosylation Truncation
2PentamericCapsomers
Infectious
Dead End?
Unanswered QuestionsUnanswered QuestionsUnanswered QuestionsUnanswered 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
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
AcknowledgementsAcknowledgements
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