Two different conformations of rabies virus glycoprotein taken under neutral pH conditions.
We previously reported that the rabies virus glycoprotein (G) takes either of two different conformations (referred to as B and C forms) under neutral pH conditions, that could be differentiated by their reactivity to a monoclonal antibody (mAb), #1-30-44, that recognizes the acid-sensitive conformational epitope, and the formation taken is dependent on two separate regions containing Lys-202 and Asn-336 of the protein (Kankanamge et al., Microbiol. Immunol., 47, 507-519, 2003). Semi-quantitative antibody-binding assays demonstrated that only one-third to one-fourth of mature G proteins on the cell surface were taking the 1-30-44 epitope-positive B form even at pH 7.4. The ratio of B to C varied, depending on the environmental pH, but did not decrease to zero even at pH 5.8-6.2, preserving a certain content (about 15-20%) of B form. Immunoprecipitation studies demonstrated that a portion of G proteins were intimately associated with a dimer form of matrix (M) protein in terms of resistance to treatment with a mixture of 1% deoxycholate and 1% Nonidet P-40, and seemed to preserve the B form even at lower pHs. Similar results were also obtained with the virion-associated G proteins, including the intimate association of a portion of the G proteins with the M protein dimer. From these results, we assume that a certain portion of the rabies virion-associated G proteins are associated with a dimer form of M protein, keeping the 1-30-44 epitope-positive B conformation under various pH conditions, which might possibly assure the virion's recognition of host cell receptor molecules in the body.
Irie
Takashi
T
Department of Molecular Microbiology, Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, Japan.
Kankanamge
Pushpa Jenette
PJ
Kawai
Akihiko
A
D000818:Animals; D000956:Antigens, Viral / Q000737:chemistry*; D006224:Cricetinae; D019281:Dimerization; D000939:Epitopes; D006023:Glycoproteins / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D011487:Protein Conformation; D011817:Rabbits; D014759:Viral Envelope Proteins / Q000737:chemistry*; D014763:Viral Matrix Proteins
D000956:Antigens, Viral; D000939:Epitopes; D006023:Glycoproteins; D014759:Viral Envelope Proteins; D014763:Viral Matrix Proteins; C064951:glycoprotein G, Rabies virus