Structural Analysis of Influenza A Virus Matrix Protein M1 and Its Self-Assemblies at Low pHстатья
Статья опубликована в высокорейтинговом журнале
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Дата последнего поиска статьи во внешних источниках: 20 декабря 2019 г.
Аннотация:Influenza A virus matrix protein M1 is one of the most important and abundant proteins in thevirus particles broadly involved in essential processes of the viral life cycle. The absence ofhigh-resolution data on the full-length M1 makes the structural investigation of the intact protein particularly important.We employed synchrotron small-angle X-ray scattering (SAXS), analytical ultracentrifugationand atomic force microscopy (AFM) to study the structure of M1at acidic pH. The low-resolution structural models built from the SAXS data reveal astructurally anisotropicM1 molecule consisting of a compact NM-fragment and an extended and partially flexible C-terminal domain.The M1 monomers co-exist in solution with a small fraction of large clustersthat have a layered architecture similar to that observed in the authentic influenza virions.AFManalysis on a lipid-like negatively charged surface revealsthat M1 forms ordered stripes correlating wellwith the clusters observed by SAXS.The free NM-domainis monomeric in acidic solution with the overall structure similar to that observed in previously determined crystal structures. The NM-domain does notspontaneously self assemble supporting the key role of the C-terminus of M1 in the formation of supramolecular structures.Our results suggest that the flexibility of the C-terminus is an essential feature, which may be responsible for the multi-functionality of the entire protein. In particular, thisflexibility couldallow M1 tostructurally organise the viral membraneto maintain the integrity and the shape of the intact influenza virus.