Influenza virus hemagglutinin spike neck architectures and interaction with model enzymes evaluated by MALDI-TOF mass spectrometry and bioinformatics tools.

Abstract

Interactions between model enzymes and the influenza virus hemagglutinin (HA) homotrimeric spike were addressed. We digested influenza virions (naturally occurring strains and laboratory reassortants) with bromelain or subtilisin Carlsberg and analyzed by MALDI-TOF mass spectrometry the resulting HA2 C-terminal segments. All cleavage sites, together with (minor) sites detected in undigested HAs, were situated in the linker region that connects the transmembrane domain to the ectodomain. In addition to cleavage at highly favorable amino acids, various alternative enzyme preferences were found that strongly depended on the HA subtype/type. We also evaluated the surface electrostatic potentials, binding cleft topographies and spatial dimensions of stem bromelain (homologically modeled) and subtilisin Carlsberg (X-ray resolved). The results show that the enzymes (∼45Å(3)) would hardly fit into the small (∼18-20Å) linker region of the HA-spike. However, the HA membrane proximal ectodomain region was predicted to be intrinsically disordered. We propose that its motions allow steric adjustment of the enzymes' active sites to the neck of the HA spike. The subtype/type-specific architectures in this region also influenced significantly the cleavage preferences of the enzymes.

• Authors: Marina V Serebryakova, Larisa V Kordyukova, Tatiana A Semashko, Alexander L Ksenofontov, Irina A Rudneva, Ekaterina A Kropotkina, Irina Yu Filippova, Michael Veit, Lyudmila A Baratova
• Journal: Virus research (Virus Res) Vol. 160 Issue 1-2 Pg. 294-304 (Sep 2011) ISSN: 1872-7492 [Electronic] Netherlands
• PMID: 21763731 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: Copyright © 2011 Elsevier B.V. All rights reserved.

Chemical References

• Hemagglutinin Glycoproteins, Influenza Virus
• Bromelains
• Subtilisins

Topics

• Bromelains (chemistry, genetics, metabolism)
• Computational Biology
• Crystallography, X-Ray
• Hemagglutinin Glycoproteins, Influenza Virus (chemistry, genetics, metabolism)
• Hydrolysis
• Models, Biological
• Models, Molecular
• Protein Interaction Mapping
• Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
• Subtilisins (chemistry, genetics, metabolism)