X-ray structures of H5 avian and H9 swine influenza virus hemagglutinins bound to avian and human receptor analogs (original) (raw)
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Journal of Virology, 2012
brane fusion. The HA receptor-binding specificity is a key determinant for the host range and transmissibility of influenza viruses. In human pandemics of the 20th century, the HA normally has acquired specificity for human-like receptors before widespread infection. Crystal structures of the H1 HA from the 2009 human pandemic (A/California/04/2009 [CA04]) in complex with human and avian receptor analogs reveal conserved recognition of the terminal sialic acid of the glycan ligands. However, favorable interactions beyond the sialic acid are found only for ␣2-6-linked glycans and are mediated by Asp190 and Asp225, which hydrogen bond with Gal-2 and GlcNAc-3. For ␣2-3-linked glycan receptors, no specific interactions beyond the terminal sialic acid are observed. Our structural and glycan microarray analyses, in the context of other high-resolution HA structures with ␣2-6and ␣2-3-linked glycans, now elucidate the structural basis of receptor-binding specificity for H1 HAs in human and avian viruses and provide a structural explanation for the preference for ␣2-6 siaylated glycan receptors for the 2009 pandemic swine flu virus.
Biochemistry, 2013
Differential interactions between influenza A virus protein hemagglutinin (HA) and α2→3 (avian) or α2→6 (human) sialylated glycan receptors play an important role in governing host specificity and adaptation of the virus. Previous analysis of HA-glycan interactions with trisaccharides showed that, in addition to the terminal sialic acid linkage, the conformation and topology of the glycans, while they are bound to HA, are key factors in regulating these interactions. Here, the solution conformation and dynamics of two representative avian and human
Glycoconjugate Journal, 2008
If we predict the host range of new or mutant influenza virus in advance, we are able to measure against pandemic human influenza immediately after the new virus emerges somewhere. Influenza viral hemagglutinin(HA)sialoside receptor interaction is a target event for in silico chemical prediction studies about the virus host range determination. We theoretically studied avian and human influenza A virus HA H3 subtype complexed with avian or human type receptor Neu5Acα(2-3 or 2-6)Gal analogues by ab initio fragment molecular orbital (FMO) method at the second order Møller-Plesset (MP2)/6-31G level, which can evaluate correctly not only electrostatic interactions but also lipophilic interactions based on van der Waals dispersion force. Avian H3 bound to avian α2-3 11.4 kcal/mol stronger than to human α2-6 in the model complexes with taking account of intermolecular lipophilic interaction. A substitution at the position 226 between Gln (avian) and Leu(human) on influenza H3 HA1 has altered Glycoconj J (2008) 25:805-815 its virus host range between avian and human. In the ab initio FMO studies, binding energy of avian Gln226Leu H3-human α2-6 was quite similar to that in the human H3human α2-6 complex with amino acid sequence differences at nine positions in the models. This similarity indicates that avian Gln226Leu H3 virus can infect human with the same level as human H3 virus. Opposite mutation Leu226Gln in the human H3 gave the moderate binding energies to avian α2-3 with similarity to avian H3-α2-3 complex that supported our previous virus-sialoside binding assay. Ab initio FMO studies have revealed the relationship between influenza H3 virus host range and H3-α(2-3 or 2-6) receptors binding. Our theoretical approach may predict the infectious level of new viruses and point out some unknown dangerous mutation positions on HA in advance.
Evolution of the receptor binding properties of the influenza A(H3N2) hemagglutinin
Proceedings of the National Academy of Sciences, 2012
The hemagglutinin (HA) of influenza A(H3N2) virus responsible for the 1968 influenza pandemic derived from an avian virus. On introduction into humans, its receptor binding properties had changed from a preference for avian receptors (α2,3-linked sialic acid) to a preference for human receptors (α2,6-linked sialic acid). By 2001, the avidity of human H3 viruses for avian receptors had declined, and since then the affinity for human receptors has also decreased significantly. These changes in receptor binding, which correlate with increased difficulties in virus propagation in vitro and in antigenic analysis, have been assessed by virus hemagglutination of erythrocytes from different species and quantified by measuring virus binding to receptor analogs using surface biolayer interferometry. Crystal structures of HA–receptor analog complexes formed with HAs from viruses isolated in 2004 and 2005 reveal significant differences in the conformation of the 220-loop of HA1, relative to the...
Crystal structures of influenza virus hemagglutinin in complex with high-affinity receptor
Structure, 1994
Background: The first step in influenza A virus infection involves attachment to cells through binding of viral hemagglutinin to cell-surface receptors containing ea-5-N-acetylneuraminic acid (sialic acid). The structures of soluble hemagglutinin in isolation and in complex with several low-affinity receptor analogs have been solved previously to approximately 3A resolution. To design effective, and possibly therapeutic, inhibitors of viral attachment we have determined the structure of hemagglutinin in complex with four high-affinity (10-fold to 100-fold higher affinity) sialic acid analogs at higher resolution. Results: In each crystal structure the sialic acid moiety is equivalently positioned in the receptor binding site but the substituent groups that differentiate the high-affinity analogs from each other interact with hydrophobic patches and polar residues adjacent to the binding site. Re-examination of the receptor binding site at 2.15 A resolution reveals several hydrophilic pockets and an apolar channel that adjoin the receptor binding site. Conclusions: The interactions observed in the structures of soluble hemagglutinin in complex with receptor analogs suggest explanations for the observed affinities of the analogs, designs for potential sialic acid analogs with even higher affinities, and ideas both for inhibiting membrane fusion and for circumventing evasion of inhibition by antigenic variation.
Structure and Receptor Complexes of the Hemagglutinin from a Highly Pathogenic H7N7 Influenza Virus
Journal of Virology, 2012
Recurrence of highly pathogenic avian influenza (HPAI) virus subtype H7 in poultry continues to be a public health concern. In 2003, an HPAI H7N7 outbreak in the Netherlands infected 89 people in close contact with affected poultry and resulted in one fatal case. In previous studies, the virus isolated from this fatal case, A/Netherlands/219/2003 (NL219) caused a lethal infection in mouse models and had increased replication efficiency and a broader tissue distribution than nonlethal isolates from the same outbreak. A mutation which introduces a potential glycosylation site at Asn123 in the NL219 hemagglutinin was postulated to contribute to the pathogenic properties of this virus. To study this further, we have expressed the NL219 hemagglutinin in a baculovirus expression system and performed a structural analysis of the hemagglutinin in complex with avian and human receptor analogs. Glycan microarray and kinetic analysis were performed to compare the receptor binding profile of the wild-type recombinant NL219 HA to a variant with a threonine-to-alanine mutation at position 125, resulting in loss of the glycosylation site at Asn123. The results suggest that the additional glycosylation sequon increases binding affinity to avian-type ␣2-3-linked sialosides rather than switching to a human-like receptor specificity and highlight the mechanistic diversity of these pathogens, which calls attention to the need for further studies to fully understand the unique properties of these viruses.
Structural basis for receptor specificity of influenza B virus hemagglutinin
Proceedings of the National Academy of Sciences, 2007
Receptor-binding specificity of HA, the major surface glycoprotein of influenza virus, primarily determines the host ranges that the virus can infect. Influenza type B virus almost exclusively infects humans and contributes to the annual “flu” sickness. Here we report the structures of influenza B virus HA in complex with human and avian receptor analogs, respectively. These structures provide a structural basis for the different receptor-binding properties of influenza A and B virus HA molecules and for the ability of influenza B virus HA to distinguish human and avian receptors. The structure of influenza B virus HA with avian receptor analog also reveals how mutations in the region of residues 194 to 196, which are frequently observed in egg-adapted and naturally occurring variants, directly affect the receptor binding of the resultant virus strains. Furthermore, these structures of influenza B virus HA are compared with known structures of influenza A virus HAs, which suggests t...
Crystallographic detection of a second ligand binding site in influenza virus hemagglutinin
Proceedings of the National Academy of Sciences, 1992
X-ray crystal structures have been determined for several complexes between influenza virus hemagglutinin and derivatives of its cell-surface receptor, sialic acid (Neu5Ac). Difference electron density maps establish the existence of a second binding site in addition to the primary site characterized previously. Three compounds bind to both sites: Neu5Ac(alpha 2-3)Gal(beta 1-4)Glc [(alpha 2-3)sialyllactose], alpha-2-O-(4'-benzylamidocarboxybutyl)-5-N-acetylneuraminic acid, and alpha-2-O-(4'-methylamidocarboxybutyl)-5-N-acetylneuraminic acid; and four other compounds bind only to the primary site: Neu5Ac(alpha 2-6)Gal(beta 1-4)Glc [(alpha 2-6)sialyllactose], alpha-2-O-methyl-5-N-acetylneuraminic acid, 4-]-acetyl-alpha-2-O-methyl-5-N-acetylneuraminic acid, and 9-amino-9-deoxy-alpha-2-O-methyl-5-N-acetylneuraminic acid. The maps also extend earlier results by showing the location of all three sugar residues of (alpha 2-3)sialyllactose in the primary binding site. The affinity o...
The structural variability of the influenza A hemagglutinin receptor-binding site
Briefings in functional genomics, 2017
Hemagglutinin (HA) is a transmembrane protein of the influenza A virus and a key component in its life cycle. The protein allows the virus to enter a host cell by recognizing specific glycans attached to transmembrane proteins of the host, which leads to viral endocytosis. In recent years, significant progress has been made in understanding the structural relationship between changes in the HA receptor-binding site (RBS) and the sialylated glycans that bind them. Several mutations were identified in the HA RBS that allows the virus to change host tropism. Their impact on binding the analogs of human and avian receptors was determined with X-ray crystallography. In this article, we provide a short overview of the HA protein structure and briefly discuss the adaptive mutations introduced to different HA subtypes.