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Trypsin cleavage stabilizes the rotavirus VP4 spike
S E Crawford1, S K Mukherjee, M K Estes
1Department of Molecular Virology and Microbiology, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA.
Journal of Virology
|June 8, 2001
Summary
Trypsin treatment orders rotavirus VP4 spikes, enhancing viral entry into cells. This structural change in rotavirus particles increases infectivity, making virus entry more efficient.
Area of Science:
- Virology
- Structural Biology
- Biochemistry
Background:
- Rotavirus infectivity is enhanced by trypsin, but the underlying mechanism is unclear.
- The structural basis for trypsin-mediated enhancement of rotavirus infectivity requires investigation.
Purpose of the Study:
- To elucidate the structural and biochemical changes in rotavirus particles induced by trypsin.
- To understand how these changes influence rotavirus infectivity.
Main Methods:
- Characterization of SA11 4F triple-layered particles (TLPs) grown with or without trypsin using electron cryomicroscopy and biochemical analysis.
- Assessment of infectivity following trypsin treatment.
Main Results:
- Nontrypsinized rotavirus (NTR) particles exhibited disordered VP4 spikes, unlike the ordered spikes in trypsinized rotavirus (TR) particles.
- Trypsin treatment of NTR particles partially restored spike structure and increased infectivity, though less than TR particles.
- Further trypsin cleavage sites in VP5(*) correlated with enhanced infectivity and structural changes in VP7.
Conclusions:
- Trypsin cleavage induces order in VP4 spikes on newly synthesized rotavirus particles.
- Ordered VP4 spikes are crucial for efficient rotavirus entry into host cells.