title: Secondary structure and membrane topology of dengue virus NS4B N-terminal 125 amino acids.
abstract: The transmembrane NS4B protein of dengue virus (DENV) is a validated antiviral target that plays important roles in viral replication and invasion of innate immune response. The first 125 amino acids of DENV NS4B are sufficient for inhibition of alpha/beta interferon signaling. Resistance mutations to NS4B inhibitors are all mapped to the first 125 amino acids. In this study, we expressed and purified a protein representing the first 125 amino acids of NS4B (NS4B(1-125)). This recombinant NS4B(1-125) protein was reconstituted into detergent micelles. Solution NMR spectroscopy demonstrated that there are five helices (α1 to α5) present in NS4B(1-125). Dynamic studies, together with a paramagnetic relaxation enhancement experiment demonstrated that four helices, α2, α3, α4, and α5 are embedded in the detergent micelles. Comparison of wild type and V63I mutant (a mutation that confers resistance to NS4B inhibitor) NS4B(1-125) proteins demonstrated that V63I mutation did not cause significant conformational changes, however, V63 may have a molecular interaction with residues in the α5 transmembrane domain under certain conditions. The structural and dynamic information obtained in study is helpful to understand the structure and function of NS4B.
authors.affiliation: Experimental Therapeutics Centre, Agency for Science, Technology and Research (A*STAR), Singapore, Singapore.
authors.forename: Yan
authors.initials: Y
authors.lastname: Li
authors.affiliation: Experimental Therapeutics Centre, Agency for Science, Technology and Research (A*STAR), Singapore, Singapore.
authors.forename: Young Mee
authors.initials: YM
authors.lastname: Kim
authors.affiliation: Novartis Institute for Tropical Diseases, Singapore, Singapore.
authors.forename: Jing
authors.initials: J
authors.lastname: Zou
authors.affiliation: Novartis Institute for Tropical Diseases, Singapore, Singapore.
authors.forename: Qing-Yin
authors.initials: QY
authors.lastname: Wang
authors.affiliation: Department of Pharmaceutical Sciences, Dr H. S. Gour University, Sagar 470003, Madhya Pradesh, India.
authors.forename: Shovanlal
authors.initials: S
authors.lastname: Gayen
authors.affiliation: Experimental Therapeutics Centre, Agency for Science, Technology and Research (A*STAR), Singapore, Singapore.
authors.forename: Ying Lei
authors.initials: YL
authors.lastname: Wong
authors.affiliation: Novartis Institute for Tropical Diseases, Singapore, Singapore.
authors.forename: Le Tian
authors.initials: le T
authors.lastname: Lee
authors.affiliation: Novartis Institute for Tropical Diseases, Singapore, Singapore.
authors.forename: Xuping
authors.initials: X
authors.lastname: Xie
authors.affiliation: Experimental Therapeutics Centre, Agency for Science, Technology and Research (A*STAR), Singapore, Singapore.
authors.forename: Qiwei
authors.initials: Q
authors.lastname: Huang
authors.affiliation: School of Biological Sciences, Nanyang Technological University, Singapore, Singapore.
authors.forename: Julien
authors.initials: J
authors.lastname: Lescar
authors.affiliation: Novartis Institute for Tropical Diseases, Singapore, Singapore. Electronic address: peshi@utmb.edu.
authors.forename: Pei-Yong
authors.initials: PY
authors.lastname: Shi
authors.affiliation: Experimental Therapeutics Centre, Agency for Science, Technology and Research (A*STAR), Singapore, Singapore. Electronic address: cbkang@etc.a-star.edu.sg.
authors.forename: CongBao
authors.initials: C
authors.lastname: Kang
mesh_terms: D002942:Circular Dichroism; D003716:Dengue Virus / Q000737:chemistry*; D009154:Mutation; D019906:Nuclear Magnetic Resonance, Biomolecular; D017433:Protein Structure, Secondary; D017361:Viral Nonstructural Proteins / Q000737:chemistry* / Q000235:genetics
chemical_list: D017361:Viral Nonstructural Proteins
keywords: Dengue virus; Membrane protein; NMR; NS4B; Paramagnetic relaxation enhancement