title: Oligomerization of Hantavirus N protein: C-terminal alpha-helices interact to form a shared hydrophobic space.
abstract: The structure of the nucleocapsid protein of bunyaviruses has not been defined. Earlier we have shown that Tula hantavirus N protein oligomerization is dependent on the C-terminal domains. Of them, the helix-loop-helix motif was found to be an essential structure. Computer modeling predicted that oligomerization occurs via helix protrusions, and the shared hydrophobic space formed by amino acids residues 380-IILLF-384 in the first helix and 413-LI-414 in the second helix is responsible for stabilizing the interaction. The model was validated by two approaches. First, analysis of the oligomerization capacity of the N protein mutants performed with the mammalian two-hybrid system showed that both preservation of the helix structure and formation of the shared hydrophobic space are crucial for the interaction. Second, oligomerization was shown to be a prerequisite for the granular pattern of transiently expressed N protein in transfected cells. N protein trimerization was supported by three-dimensional reconstruction of the N protein by electron microscopy after negative staining. Finally, we discuss how N protein trimerization could occur.
authors.affiliation: Department of Virology, Haartman Institute, P.O. Box 21, FI-00014 University of Helsinki, Finland. antti.vaheri@helsinki.fi.
authors.forename: Pasi
authors.initials: P
authors.lastname: Kaukinen
authors.forename: Vibhor
authors.initials: V
authors.lastname: Kumar
authors.forename: Kirsi
authors.initials: K
authors.lastname: Tulimäki
authors.forename: Peter
authors.initials: P
authors.lastname: Engelhardt
authors.forename: Antti
authors.initials: A
authors.lastname: Vaheri
authors.forename: Alexander
authors.initials: A
authors.lastname: Plyusnin
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D019556:COS Cells; D002522:Chlorocebus aethiops; D019281:Dimerization; D006476:Orthohantavirus / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D006367:HeLa Cells; D018257:Helix-Loop-Helix Motifs; D006801:Humans; D008958:Models, Molecular; D008969:Molecular Sequence Data; D019590:Nucleocapsid Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D017433:Protein Structure, Secondary; D020798:Two-Hybrid System Techniques
chemical_list: D019590:Nucleocapsid Proteins