Biological complexity: how viurses attack bacteria (Introduction)

by David Turell , Wednesday, May 18, 2016, 18:47 (3111 days ago) @ dhw

Bacteriophages are viruses who attack bacteria. Here is how they inject your DNA control mechanisms:-http://phys.org/news/2016-05-viruses-infect-bacteria-tale-tail.html-"To infect bacteria, most bacteriophages employ a 'tail' that stabs and pierces the bacterium's membrane to allow the virus's genetic material to pass through. The most sophisticated tails consist of a contractile sheath surrounding a tube akin to a stretched coil spring at the nanoscale. When the virus attaches to the bacterial surface, the sheath contracts and drives the tube through it. All this is controlled by a million-atom baseplate structure at the end of the tail. EPFL scientists have now shown, in atomic detail, how the baseplate coordinates the virus's attachment to a bacterium with the contraction of the tail's sheath. -***-"The laboratory of Petr Leiman at EPFL has now created a detailed, atom-level model of the transformation of a phage's baseplate, an important structure that controls the phage's ability to find its target bacterium and attach to it, contract its tail, and inject its DNA. The entire baseplate-tail-tube complex consists of one million atoms, making up 145 chains of 15 different proteins, most of which had to be modeled from scratch. To do this, Leiman's lab used the state-of-the-art equipment of the Center for Cellular Imaging and NanoAnalytics (C-CINA) at the University of Basel and the computing resources of EPFL's High Performance Computing department.-"The scientists were also able to identify a minimal set of molecular components in the baseplate that work together like miniature gears to control the activity of the virus's tail. These components, and the underlying functional mechanism, are the same across many viruses and even bacteria that use similar tail-like structures to inject toxins into neighboring cells.-The laboratory of Petr Leiman at EPFL has now created a detailed, atom-level model of the transformation of a phage's baseplate, an important structure that controls the phage's ability to find its target bacterium and attach to it, contract its tail, and inject its DNA. The entire baseplate-tail-tube complex consists of one million atoms, making up 145 chains of 15 different proteins, most of which had to be modeled from scratch. To do this, Leiman's lab used the state-of-the-art equipment of the Center for Cellular Imaging and NanoAnalytics (C-CINA) at the University of Basel and the computing resources of EPFL's High Performance Computing department.-"The scientists were also able to identify a minimal set of molecular components in the baseplate that work together like miniature gears to control the activity of the virus's tail. These components, and the underlying functional mechanism, are the same across many viruses and even bacteria that use similar tail-like structures to inject toxins into neighboring cells."-Comment: How did viruses develop this level of complexity? All of biology shows this, not by chance!