Mapping of the Hepatitis B Virus Pre-S1 Domain Involved in Receptor Recognition

Abstract

Hepatitis B virus (HBV) and woolly monkey hepatitis B virus (WMHBV) are primate hepadnaviruses that display restricted tissue and host tropisms. Hepatitis D virus (HDV) particles pseudotyped with HBV and WMHBV envelopes (HBV-HDV and WM-HDV) preferentially infect human and spider monkey hepatocytes, respectively, thereby confirming host range bias in vitro. The analysis of chimeric HBV and WMHBV large (L) envelope proteins suggests that the pre-S1 domain may comprise two regions that affect infectivity: one within the amino-terminal 40 amino acids of pre-S1 and one downstream of this region. In the present study, we further characterized the role of the amino terminus of pre-S1 in infectivity by examining the ability of synthetic peptides to competitively block HDV infection of primary human and spider monkey hepatocytes. A synthetic peptide representing the first 45 residues of the pre-S1 domain of the HBV L protein blocked infectivity of HBV-HDV and WM-HDV, with a requirement for myristylation of the amino terminal residue. Competition studies with truncated peptides suggested that pre-S1 residues 5 to 20 represent the minimal domain for inhibition of HDV infection and, thus, presumably represent the residues involved in virus-host receptor interaction. Recombinant pre-S1 proteins expressed in insect cells blocked infection with HBV-HDV and WM-HDV at a concentration of 1 nanomolar. The ability of short pre-S1 peptides to efficiently inhibit HDV infection suggests that they represent suitable ligands for identification of the HBV receptor and that a pre-S1 mimetic may represent a rational therapy for the treatment of HBV infection.The hepatitis B virus (HBV) genome is a relaxed-circular, partially duplex DNA with a covalently attached polymerase that displays reverse transcriptase activities (40,41). The viral glycoproteins contained in the HBV envelope are encoded by a single open reading frame (ORF) and are translated from different in-frame start codons to generate the small (S), middle (M), and large (L) proteins. All three proteins contain the surface domain (S), while the M protein has a 55-amino-acid (aa) extension designated the pre-S2 domain and the L protein contains an additional 108-aa pre-S1 domain. The L protein is modified at the amino-terminal glycine of the pre-S1 domain with a myristate (37), which is required for infectivity (4, 10, 32). The pre-S1 domain of the L glycoprotein has long been implicated in receptor binding and host range (5,29,43), yet, almost 40 years after the discovery of HBV, no receptor has been positively identified. Receptor candidates that are pre-S1-binding proteins have included the interleukin-6 receptor (35) and an immunoglobulin A-binding protein on hepatocytes (38). More recently, two groups have identified additional pre-S1-binding proteins. Ryu et al. identified an 80-kDa protein using a glutathione S-transferase-pre-S1 fusion protein (39), while De Falco et al. identified a 44-kDa protein (6) by using the pre-S1 peptide originally shown to bind liver cells by Ne...

Hepatitis B virus infection initiates with a large surface protein-dependent binding to heparan sulfate proteoglycans

“…6,7 (3) The integrity of the N-terminal 77 amino acids is essential for infectivity, whereas the preS2 domain is dispensable. 8,9 (4) Acylated peptides comprising the Nterminal 47 amino acids of the preS1 domain abolish HBV infection in vitro [10][11][12][13] and in vivo (Petersen et al, unpublished observations, 2007).…”

An anti-viral peptide derived from the preS1 surface protein of hepatitis B virus

“…An early study which suggested that the preS2 portion of HBV might mediate binding of viral particles to hepatocytes (32) was determined to be false. Even though it has been well established that the preS1 is most critical for HBV infection there has not been a consensus on which region(s) of the preS1 is most critical for infection (14)(15)(16)(17)(18)(19)(20). In addition to the absence of structural knowledge on the preS1 domain another, perhaps more serious, bottleneck in delineating effective preS1 domains responsible for HBV attachment was the lack of an efficient cell culture assay system.…”

“…Even though the former utilizes a peptide fragment and the latter a small chemical compounds they both rely on the same strategy, blocking initial viral entry. In order to develop an anti-HBV agent following a similar strategy several investigators attempted to map the regions(s) of HBV surface proteins that would be crucial for the initial binding of HBV to a putative hepatocyte receptor (14)(15)(16)(17)(18)(19)(20). An early study which suggested that the preS2 portion of HBV might mediate binding of viral particles to hepatocytes (32) was determined to be false.…”

“…This conclusion strongly suggests that preS1-derived peptides hold great promise as an effective HBV-blocking agent (14)(15)(16)(17)(18)(19). Several studies, including an early study that proposed the residues 21-47 in preS1 are important for HBV binding to a putative hepatocyte receptor (20), have demonstrated that the N-terminal half of the preS1 is vital for viral attachment to host cells (14)(15)(16)(17)(18)(19). Nevertheless results from different studies failed to provide a consensus preS1 sequence that would be effective against HBV infection.…”

Variantes de escape del virus de la hepatitis B

“…Los dominios más importantes del HBsAg son: el sitio de unión al receptor del hepatocito, aminoácidos 21-47 de la forma L, que además es esencial para el ensamble y salida de los viriones [25][26][27] ; el dominio ubicado entre los residuos 29-79 que forma el principal "loop" citoplasmático y mediante el cual interactúa con HBcAg; el dominio entre los aminoácidos 3-16 en la forma M, que se une al sitio de polimerización de la albumina, y la principal región hidrofílica, localizada entre los residuos 101-169 de la forma S, que incluye el determinante "a" (aminoácidos 124-147), el cual adquiere su conformación debido a dos puentes disulfuro [28][29] .…”