.<\/p>\n
When the human body becomes infected with new
\n influenza viruses, the immune system rapidly activates
\n an inborn protective mechanism to inhibit the intruding
\n pathogen. A protein known as Mx plays an important role
\n in this process, keeping the spread of viruses in check.
\n Exactly how Mx accomplishes this task was previously
\n unknown. Now virologists from the Institute of Medical
\nMicrobiology at the Freiburg University Medical Center
\n and structural biologists from the Max Delbr\u00fcck
\nCenter for Molecular Medicine (MDC) in Berlin-Buch,
\nGermany, have unraveled the structure of the Mx protein and
\nare able to explain how it develops its anti-viral effect
\n (Nature, doi: 10.1038\/nature08972)*.
\n.<\/p>\n
New influenza viruses jump from animals to humans
\n with alarming frequency, as evidenced by the H5N1
\nbird flu virus or, more recently, with the swine flu virus.
\nAlthough humans usually do not have any preexisting
\nimmunity to such pathogens, they are not completely
\n unprotected against the invaders. The human body can
\n rapidly mobilize a defense strategy which prevents the
\n influenza viruses from proliferating unchecked in the body.
\n.<\/p>\n
An essential element of this protection is a protein,
\nknown as Mx (short for myxovirus resistance), produced
\nby the body which recognizes many viruses and prevents
\nthem from replicating inside infected cells. Under normal
\n conditions this protective protein is not present in the cell
\nat all, but after infection it can be produced in large quantities.
\n The order to produce this protein Mx is made by the
\nsignaling protein interferon, which is excreted by infected
\n cells and alarms the organism of the virus infection.<\/p>\n
. <\/p>\n
Mx is a molecular machine which does not develop
\nits full power until the individual molecules have joined
\n to form a ring-structured macromolecular network. A
\ncentral element of the formation of these ring structures
\n is the special part of Mx known as the stalk.<\/p>\n
.<\/p>\n
Scientists have attempted to describe the structure
\nof this stalk for years. The virologists Otto Haller,
\n Alexander von der Malsburg, and Georg Kochs in Freiburg
\n and the structural biologists Oliver Daumke, Song Gao,
\nSusann Paeschke, and Joachim Behlke from MDC in
\nBerlin-Buch have now unraveled the secret of the stalk structure
\n of Mx at the atomic level. This structure explains the
\ncomposition of Mx and allows scientists to conduct tests to
\nmake predictions concerning the mode of action of the
\nantiviral molecule. <\/p>\n
. <\/p>\n
In combination with findings from earlier biochemical
\nstudies, the results of this study make it clear that the
\nstalk structure of Mx functions as a kind of clamp which
\n restrains and deactivates important components of the
\ninfluenza virus in the infected cell. The fact that new forms
\n of flu can lead to epidemics or even pandemics in spite
\nof this defense mechanism is due to the power and
\naggressiveness of these pathogens. <\/p>\n
.<\/p>\n
The researchers are confident that their new findings
\nabout the protective Mx protein will form the basis for the
\n development of new antiviral drugs for combating
\ndangerous influenza viruses. Moreover, they are also
\n certain that this new knowledge about the function of Mx
\nwill increase their understanding of other members of this
\n family of proteins. <\/p>\n
.<\/p>\n
A computer model of the protein may be downloaded at: <\/strong> . . When the human body becomes infected with new influenza viruses, the immune system rapidly activates an inborn protective mechanism to inhibit the intruding pathogen. A protein known as Mx plays an important role in this process, keeping the spread of viruses in check. Exactly how Mx accomplishes this task was previously unknown. Now virologists … <\/p>\n
\n.
\nhttp:\/\/www.mdc-berlin.de\/de\/index.html<\/a><\/p>\n
\n.<\/p>\n","protected":false},"excerpt":{"rendered":"