PMID- 9375809
OWN - NLM
STAT- MEDLINE
DCOM- 19971210
LR  - 20190610
IS  - 0006-3002 (Print)
IS  - 0006-3002 (Linking)
VI  - 1330
IP  - 1
DP  - 1997 Nov 13
TI  - Pores formed by influenza hemagglutinin.
PG  - 17-28
AB  - Low pH-induced fusion mediated by the hemagglutinin (HA) of influenza virus 
      involves a conformational change in the protein that leads to the insertion of a 
      "fusion peptide" of the protein into the target membrane. It has been suggested 
      that this insertion, aided by the formation of a complex of multiple HA trimers, 
      would lead to perturbation of the bilayer structure of the membrane, initiating 
      fusion. Here we present data showing that the interaction of the bromelain 
      released ectodomain of the protein (BHA) with liposomal membranes at low pH leads 
      to pore formation, at least at low temperatures. Strongly temperature-dependent 
      low pH-induced inactivation of BHA resulted in a complete lack of activity of BHA 
      above 10 degrees C. Even at 0 degrees C, only about 5% of the BHA participated in 
      pore formation. Viral HA was less rapidly inactivated and still induced pores at 
      37 degrees C. BHA-induced pore formation showed a sigmoidal time course. Once BHA 
      had formed a pore in one liposome, it did not form a pore in a further liposome. 
      Quantitative analysis of pore formation indicated that one single BHA trimer 
      sufficed to produce a pore. These data indicate that fusion peptide insertion 
      perturbs the membrane and that the formation of a complex of trimers is not a 
      prerequisite for the perturbation.
FAU - Jiricek, R
AU  - Jiricek R
AD  - Department of Biophysical Chemistry, Biozentrum of the University of Basel, 
      Switzerland.
FAU - Schwarz, G
AU  - Schwarz G
FAU - Stegmann, T
AU  - Stegmann T
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PL  - Netherlands
TA  - Biochim Biophys Acta
JT  - Biochimica et biophysica acta
JID - 0217513
RN  - 0 (Hemagglutinin Glycoproteins, Influenza Virus)
RN  - 0 (Lipid Bilayers)
RN  - 0 (Liposomes)
SB  - IM
MH  - Cold Temperature
MH  - Diffusion
MH  - Hemagglutinin Glycoproteins, Influenza Virus/*physiology
MH  - Hydrogen-Ion Concentration
MH  - Lipid Bilayers
MH  - Liposomes
MH  - Membrane Fusion
EDAT- 1997/12/31 00:00
MHDA- 1997/12/31 00:01
CRDT- 1997/12/31 00:00
PHST- 1997/12/31 00:00 [pubmed]
PHST- 1997/12/31 00:01 [medline]
PHST- 1997/12/31 00:00 [entrez]
AID - S0005-2736(97)00134-X [pii]
AID - 10.1016/s0005-2736(97)00134-x [doi]
PST - ppublish
SO  - Biochim Biophys Acta. 1997 Nov 13;1330(1):17-28. doi: 
      10.1016/s0005-2736(97)00134-x.