Mutational analysis of hepatitis B virus pre-S1 (9-24) fusogenic peptide.
A hollow nanoparticle known as a bio-nanocapsule (BNC) consisting of hepatitis B virus (HBV) envelope L protein and liposome (LP) can encapsulate drugs and genes and thereby deliver them in vitro and in vivo to human hepatic tissues, specifically by utilizing the HBV-derived infection machinery. Recently, we identified a low pH-dependent fusogenic domain at the N-terminal part of the pre-S1 region of the HBV L protein (amino acid residues 9 to 24; NPLGFFPDHQLDPAFG), which shows membrane destabilizing activity (i.e., membrane fusion, membrane disruption, and payload release) upon interaction with target LPs. In this study, instead of BNC and HBV, we generated LPs displaying a mutated form of the pre-S1 (9-24) peptide, and performed a membrane disruption assay using target LPs containing pyranine (fluorophore) and p-xylene-bis (N-pyridinium bromide) (DPX) as a quencher. The membrane disruption activity was found to correlate with the hydrophobicity of the whole structure, while the peptide retained a random-coil structure even under low pH condition. One large hydrophobic cluster (I) and one small hydrophobic cluster (II) residing in the peptide would be connected by the protonation of residues D16 and D20, and thereby exhibit strong membrane disruption activity in a low pH-dependent manner. Furthermore, the introduction of a positively charged residue enhanced the activity significantly, suggesting that a sole positively charged residue (H17) may be important for the interaction with target LPs by electrostatic interaction. Collectively, these results suggest that the pre-S1 (9-24) peptide may be involved in the endosomal escape of the BNC's payloads, as well as in the HBV uncoating process.
The Institute of Scientific and Industrial Research, Osaka University, Osaka 567-0047, Japan.
Qiushi
Q
Liu
The Institute of Scientific and Industrial Research, Osaka University, Osaka 567-0047, Japan.
Masaharu
M
Somiya
Department of Biomolecular Engineering, Tokyo Institute of Technology, 4259 B-57, Nagatsuta, Midori, Yokohama 226-8501, Japan.
Naohiko
N
Shimada
Department of Biomolecular Engineering, Tokyo Institute of Technology, 4259 B-57, Nagatsuta, Midori, Yokohama 226-8501, Japan.
Wakako
W
Sakamoto
The Institute of Scientific and Industrial Research, Osaka University, Osaka 567-0047, Japan.
Nobuo
N
Yoshimoto
The Institute of Scientific and Industrial Research, Osaka University, Osaka 567-0047, Japan.
Masumi
M
Iijima
The Institute of Scientific and Industrial Research, Osaka University, Osaka 567-0047, Japan.
Kenji
K
Tatematsu
The Institute of Scientific and Industrial Research, Osaka University, Osaka 567-0047, Japan.
Tadashi
T
Nakai
The Institute of Scientific and Industrial Research, Osaka University, Osaka 567-0047, Japan.
Toshihide
T
Okajima
Department of Biomolecular Engineering, Tokyo Institute of Technology, 4259 B-57, Nagatsuta, Midori, Yokohama 226-8501, Japan.
Atsushi
A
Maruyama
The Institute of Scientific and Industrial Research, Osaka University, Osaka 567-0047, Japan. Electronic address: skuroda@sanken.osaka-u.ac.jp.
Shuńichi
S
Kuroda
D001483:Base Sequence; D002462:Cell Membrane / Q000737:chemistry*; D004252:DNA Mutational Analysis / Q000379:methods*; D006514:Hepatitis B Surface Antigens / Q000737:chemistry* / Q000235:genetics*; D006515:Hepatitis B virus / Q000235:genetics*; D006863:Hydrogen-Ion Concentration; D057927:Hydrophobic and Hydrophilic Interactions; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics*; D020641:Polymorphism, Single Nucleotide / Q000235:genetics; D000072417:Protein Domains / Q000235:genetics; D011498:Protein Precursors / Q000737:chemistry* / Q000235:genetics*
D006514:Hepatitis B Surface Antigens; D011498:Protein Precursors; C050806:presurface protein 1, hepatitis B surface antigen
Bio-nanocapsule; Endosomal escape; Fusion peptide; Hepatitis B virus; Hydrophobicity; Membrane disruption