title: [Study on functions of N-carbohydrate chains in human parainfluenza virus type 3 hemagglutinin-neuraminidase protein].
abstract: To determine the functions of N-carbohydrate chains in human parainfluenza virus type 3 hemagglutinin-neuraminidase(HN) protein, a PCR-based site-directed mutagenesis method was used to obtain N-glycan mutants. Protein electrophoresis rate, cell surface expression,receptor binding activity, neuraminidase activity and cell fusion promotion activity were determined. The HN proteins of single mutants (G1, G2, and G4) and multiple mutants (G12, G14, G24 and G124) migrated faster than the wild-type (wt) HN protein on polyacrylamide gels, while G3-mutated protein and wt HN protein migrated at the same position. There was no statistic difference in cell surface expression and neuraminidase activity between wt and each mutant HN protein (P>0.05), but receptor binding activity and cell fusion promotion activity of each mutant protein was reduced to significant extent (P<0.05). G1, G2 and G4 mutants exhibited re duced receptor binding activity, which was 83.94%, 76.45% and 55.32% of the wt level, respectively. G1, G2 and G4-mutated proteins also showed reductions in fusion promotion activity, which was 80.84%, 77.83% and 64.16%, respectively. Multiple mutants with G12-, G14-, G24- and G124- substitutions could further reduce receptor binding activities, 33.07%, 20.67%, 19.96% and 15.11% of the wt HN level, respectively. G12, G14, G24 and G124 mutants exhibited levels of fusion promotion activity that were only 46.360, 12.04%, 13.43% and 4.05% of the wt amount, respectively. As N-glycans of hPIV3 HN protein play an important role in receptor binding activity and cell fusion promotion activity of HN protein. We propose that the loss of N-glycans change the conformation or orientation of globular domain that is responsible for receptor binding and lower receptor binding activity and cell fusion promotion activi ty.
authors.affiliation: Department of Virology, School of Public Health, Shandong University, Jinan 250012, China. cfl032201088@163.com
authors.forename: Fu-lu
authors.initials: FL
authors.lastname: Chu
authors.affiliation: Department of Virology, School of Public Health, Shandong University, Jinan 250012, China.
authors.forename: Hong-ling
authors.initials: HL
authors.lastname: Wen
authors.affiliation: Institute of Experimental Nuclear Medicine, School of Medicine, Shandong University, Jinan 250012, China.
authors.forename: Gui-hua
authors.initials: GH
authors.lastname: Hou
authors.affiliation: Shandong Center for Disease Control and Prevention, J inan 250014, China.
authors.forename: Bin
authors.initials: B
authors.lastname: Lin
authors.affiliation: Shandong Center for Disease Control and Prevention, J inan 250014, China.
authors.forename: Wen-qiang
authors.initials: WQ
authors.lastname: Zhang
authors.affiliation: Department of Virology, School of Public Health, Shandong University, Jinan 250012, China.
authors.forename: Yan-yan
authors.initials: YY
authors.lastname: Song
authors.affiliation: Institute of Biochemistry and Molecular Biology, School of Medicine, Shandong University, Jinan 50012, China.
authors.forename: Gui-jie
authors.initials: GJ
authors.lastname: Ren
authors.affiliation: Department of Virology, School of Public Health, Shandong University, Jinan 250012, China.
authors.forename: Cheng-xi
authors.initials: CX
authors.lastname: Sun
authors.affiliation: Department of Virology, School of Public Health, Shandong University, Jinan 250012, China.
authors.forename: Zhen-mei
authors.initials: ZM
authors.lastname: Li
authors.affiliation: Department of Virology, School of Public Health, Shandong University, Jinan 250012, China.
authors.forename: Zhi-yu
authors.initials: ZY
authors.lastname: Wang
mesh_terms: D006031:Glycosylation; D015707:HN Protein / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D009154:Mutation; D010224:Parainfluenza Virus 3, Human / Q000737:chemistry / Q000201:enzymology* / Q000235:genetics / Q000502:physiology; D011485:Protein Binding; D011991:Receptors, Virus / Q000378:metabolism; D010253:Respirovirus Infections / Q000378:metabolism / Q000821:virology*; D053586:Virus Internalization
chemical_list: D015707:HN Protein; D011991:Receptors, Virus