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C-terminal Trimerization, but Not N-terminal Trimerization, of the Reovirus Cell Attachment Protein Is a Posttranslational and Hsp70/ATP-dependent Process
- Source :
- Journal of Biological Chemistry. 271:8466-8471
- Publication Year :
- 1996
- Publisher :
- Elsevier BV, 1996.
-
Abstract
- The C-terminal globular head of the lollipop-shaped final sigma1 protein of reovirus is responsible for interaction with the host cell receptor. Like the N-terminal fibrous tail, it has its own trimerization domain. Whereas N-terminal trimerization (formation of a triple alpha-helical coiled coil) occurs at the level of polysomes (i.e. cotranslationally) and is ATP-independent, C-terminal trimerization is a posttranslational event that requires ATP. Coprecipitation experiments using anti-Hsp70 antibodies and truncated final sigma1 proteins synthesized in vitro revealed that only regions downstream of the N-terminal alpha-helical coiled coil were associated with Hsp70. Hsp70 was also found to be associated with nascent final sigma1 chains on polysomes as well as with immature postribosomal final sigma1 trimers (hydra-like intermediates with assembled N termini and unassembled C termini). These latter structures were true intermediates in the final sigma1 biogenetic pathway since they could be chased into mature final sigma1 trimers with the release of Hsp70. Thus, unlike N-terminal trimerization, C-terminal trimerization is Hsp70- and ATP-dependent. The involvement of two mechanistically distinct oligomerization events for the same molecule, one cotranslational and one posttranslational, may represent a common approach to the generation of oligomeric proteins in the cytosol.
- Subjects :
- Protein Folding
Macromolecular Substances
Plasma protein binding
Biology
Biochemistry
Cell-free system
Structure-Activity Relationship
Viral Proteins
Adenosine Triphosphate
Polysome
Protein biosynthesis
Animals
Structure–activity relationship
HSP70 Heat-Shock Proteins
Molecular Biology
Sequence Deletion
Coiled coil
Cell-Free System
Cell Biology
Cytosol
Protein Biosynthesis
Biophysics
Receptors, Virus
Capsid Proteins
Protein folding
Rabbits
Protein Processing, Post-Translational
Molecular Chaperones
Protein Binding
Subjects
Details
- ISSN :
- 00219258
- Volume :
- 271
- Database :
- OpenAIRE
- Journal :
- Journal of Biological Chemistry
- Accession number :
- edsair.doi.dedup.....8379ef2de39a0026e69a8afb13a6c515