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SUMMARY:New Insights into Nature of Self-Assembly of Influenza А Virus Ma
 trix Protein M1 at Different Conditions: SAXS & AFM Study\, and Modeling
DTSTART;VALUE=DATE-TIME:20160705T090000Z
DTEND;VALUE=DATE-TIME:20160705T100000Z
DTSTAMP;VALUE=DATE-TIME:20260513T074058Z
UID:indico-contribution-1180@indico.inp.nsk.su
DESCRIPTION:Speakers: Eleonora Shtykova (Shubnikov Institute of Crystallog
 raphy of Federal Scientific Research Centre “Crystallography and Photoni
 cs” of Russian Academy of Sciences)\nInfluenza A viruses are important p
 athogens that still rank among the major global health problems. Matrix pr
 otein M1 in the virus particles is one of the most important and abundant 
 proteins broadly involved in essential processes of the viral life cycle. 
  It makes the structural investigation of the M1 protein particularly impo
 rtant. We employed synchrotron small-angle X-ray scattering (SAXS) and ato
 mic force microscopy (AFM) to study the structure of M1 at different condi
 tions. The low-resolution structural models built from the SAXS data revea
 l a structurally anisotropic M1 molecule consisting of a compact NM-fragme
 nt and an extended and partially flexible C-terminal domain [1]. We demons
 trated also that even at low pH the M1 monomers co-exist in solution with 
 a small fraction of large clusters possessing a layered architecture simil
 ar to that observed in the authentic influenza virions. AFM analysis on a 
 lipid-like negatively charged surface reveals that M1 forms ordered stripe
 s correlating well with the clusters observed by SAXS [1]. Low pH conditio
 n occurs at the very beginning of cell infection leading to an acid-trigge
 red fusion of the viral membrane. Moreover\, change of pH was found to ser
 ve as a impuls allowing M1 to carry out its multiple functions in the unco
 ating\, nuclear transport\, and assembly of the viral ribonucleocapsid [2]
 . Revealed by us helix-like shapes could be treated as pre-matrix protein 
 superstructures\, whose formation is an intrinsic biological property of t
 he M1 protein. It can be assumed\, however\, that the oligomerization of M
 1 should strongly depend on pH and on the protein charge. That is why it w
 as important to analyse the structure and self-assembly of M1 at gradually
  changing pH (up to the neutral pH condition) in solution and on the bare 
 mica surface using SAXS and AFM\, correspondingly. We found that the oligo
 merization processes occur in a similar way in the solution and on the sub
 strate\, and quantitatively described these processes. Moreover\, pH 6.0 w
 as found to be the condition at which binding between M1 molecules starts 
 to break. Our results provide new insights into the mechanism of M1 to for
 m matrix and virus-like particles alone without partners and give a basis 
 for a further analysis of the hierarchy of M1 in the virus life cycle.\n\n
 This work was supported in part by Russian Foundation for Basic Researches
  (projects 15-54-74002 EMBL and 16-04-00563) \n\nReferences\n1.    E. Shty
 kova et al. PLoS One\, 8\, (2013) e82431.\n2.    M. Bu et al. J. Virology\
 , 70\, (1996) 8391-8401.\n\nhttps://indico.inp.nsk.su/event/3/contribution
 s/1180/
LOCATION:Budker INP 2nd and 3rd floors
URL:https://indico.inp.nsk.su/event/3/contributions/1180/
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