Faculty Collaboration Database

Conformational and functional analysis of the C-terminal globular head of the reovirus cell attachment protein. Virology 1991 Jun;182(2):810-9

Date

06/01/1991

Pubmed ID

2024499

DOI

10.1016/0042-6822(91)90622-i

Scopus ID

2-s2.0-0025727528 (requires institutional sign-in at Scopus site)   38 Citations

Abstract

We have been investigating structure-function relationships in the reovirus cell attachment protein sigma 1 using various deletion mutants and protease analysis. In the present study, a series of deletion mutants were constructed which lacked 90, 44, 30, 12, or 4 amino acids from the C-terminus of the 455-amino acid-long reovirus type 3 (T3) sigma 1 protein. The full-length and truncated sigma 1 proteins were expressed in an in vitro transcription/translation system and assayed for L cell binding activity. It was found that the removal of as few as four amino acids from the C-terminus drastically affected the cell binding function of the sigma 1 protein. The C-terminal-truncated proteins were further characterized using trypsin, chymotrypsin, and monoclonal and polyclonal antibodies. Our results indicated that the C-terminal portions of the mutant proteins were misfolded, leading to a loss in cell binding function. The N-terminal fibrous tail of the proteins was unaffected by the deletions as was sigma 1 oligomerization, further illustrating the discrete structural and functional roles of the N- and C-terminal domains of sigma 1. In an attempt to identify smaller, functional peptides, full-length sigma 1 expressed in vitro was digested with trypsin and subsequently with chymotrypsin under various conditions. The results clearly demonstrated the highly stable nature of the C-terminal globular head of sigma 1, even when separated from the N-terminal fibrous tail. We concluded that: (1) the C-terminal globular head of sigma 1 exists as a compact, protease-resistant oligomeric structure; (2) an intact C-terminus is required for proper head folding and generation of the conformationally dependent cell binding domain.

Author List

Duncan R, Horne D, Strong JE, Leone G, Pon RT, Yeung MC, Lee PW

Author

Gustavo Leone PhD Sr Associate Dean, Director, Professor in the Pathology department at Medical College of Wisconsin

MESH terms used to index this publication - Major topics in bold

Amino Acid Sequence
Capsid Proteins
Chymotrypsin
Cloning, Molecular
DNA Mutational Analysis
In Vitro Techniques
Molecular Sequence Data
Molecular Weight
Protein Binding
Protein Conformation
Reoviridae
Restriction Mapping
Structure-Activity Relationship
Trypsin
Viral Proteins