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Crystal structure of human T cell leukemia virus type 1 gp21 ectodomain crystallized as a maltose-binding protein chimera reveals structural evolution of retroviral transmembrane proteins
- Source :
- Proceedings of the National Academy of Sciences of the United States of America. 96(8)
- Publication Year :
- 1999
-
Abstract
- Retroviral entry into cells depends on envelope glycoproteins, whereby receptor binding to the surface-exposed subunit triggers membrane fusion by the transmembrane protein (TM) subunit. We determined the crystal structure at 2.5-Å resolution of the ectodomain of gp21, the TM from human T cell leukemia virus type 1. The gp21 fragment was crystallized as a maltose-binding protein chimera, and the maltose-binding protein domain was used to solve the initial phases by the method of molecular replacement. The structure of gp21 comprises an N-terminal trimeric coiled coil, an adjacent disulfide-bonded loop that stabilizes a chain reversal, and a C-terminal sequence structurally distinct from HIV type 1/simian immunodeficiency virus gp41 that packs against the coil in an extended antiparallel fashion. Comparison of the gp21 structure with the structures of other retroviral TMs contrasts the conserved nature of the coiled coil-forming region and adjacent disulfide-bonded loop with the variable nature of the C-terminal ectodomain segment. The structure points to these features having evolved to enable the dual roles of retroviral TMs: conserved fusion function and an ability to anchor diverse surface-exposed subunit structures to the virion envelope and infected cell surface. The structure of gp21 implies that the N-terminal fusion peptide is in close proximity to the C-terminal transmembrane domain and likely represents a postfusion conformation.
- Subjects :
- Models, Molecular
Macromolecular Substances
Recombinant Fusion Proteins
Protein domain
Molecular Sequence Data
Retroviridae Proteins, Oncogenic
Biology
Gp41
Crystallography, X-Ray
Maltose-Binding Proteins
Protein Structure, Secondary
Evolution, Molecular
Protein structure
Computer Graphics
Humans
Amino Acid Sequence
Peptide sequence
Coiled coil
Human T-lymphotropic virus 1
Multidisciplinary
Sequence Homology, Amino Acid
env Gene Products, Human Immunodeficiency Virus
Gene Products, env
Biological Sciences
Molecular biology
Transmembrane protein
Cell biology
Transmembrane domain
Ectodomain
Carrier Proteins
Crystallization
Sequence Alignment
Subjects
Details
- ISSN :
- 00278424
- Volume :
- 96
- Issue :
- 8
- Database :
- OpenAIRE
- Journal :
- Proceedings of the National Academy of Sciences of the United States of America
- Accession number :
- edsair.doi.dedup.....e8212f0ebdbf665c49d9a758e971136d