Crystal structure of a h5n1 influenza virus hemagglutinin at ph 6.5
Structure:
Hemagglutinin. Chain: a. Engineered: yes
Source:
Influenza a virus (a/chicken/vietnam/4/2003(h5n1)). Organism_taxid: 380835. Strain: a/chicken/vietnam/4/2003(h5n1). Gene: ha. Expressed in: trichoplusia ni. Expression_system_taxid: 7111
Resolution:
2.39Å
R-factor:
0.216
R-free:
0.261
Authors:
A.Antanasijevic,M.A.Durst,A.Lavie,M.Caffrey
Key ref:
A.Antanasijevic
et al.
(2020).
Identification of a pH sensor in Influenza hemagglutinin using X-ray crystallography.
J Struct Biol,
209,
107412.
PubMed id: 31689502
DOI: 10.1016/j.jsb.2019.107412
Identification of a pH sensor in Influenza hemagglutinin using X-ray crystallography.
A.Antanasijevic,
M.A.Durst,
A.Lavie,
M.Caffrey.
ABSTRACT
Hemagglutnin (HA) mediates entry of influenza virus through a series of
conformational changes triggered by the low pH of the endosome. The residue or
combination of residues acting as pH sensors has not yet been fully elucidated.
In this work, we assay pH effects on the structure of H5 HA by soaking HA
crystallized at pH 6.5 in a series of buffers with lower pH, mimicking the
conditions of the endosome. We find that HA1-H38, which is conserved in Group 1
HA, undergoes a striking change in side chain conformation, which we attribute
to its protonation and cation-cation repulsion with conserved HA1-H18. This work
suggests that x-ray crystallography can be applied for studying small-scale
pH-induced conformational changes providing valuable information on the location
of pH sensors in HA. Importantly, the observed change in HA1-H38 conformation is
further evidence that the pH-induced conformational changes of HA are the result
of a series of protonation events to conserved and non-conserved pH sensors.
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