Clever bacteria: E. coli drug protection system (Introduction)

by David Turell , Monday, February 22, 2016, 18:05 (2979 days ago) @ David Turell

E. Coli, like all gram negative bacteria have protective biochemical complexes in their walls to stop harmful drugs or other chemicals to enter:-http://phys.org/news/2016-02-scientists-pave-superbug-drugs.html-"Gram-negative bacteria is particularly resistant to antibiotics because of its cells' impermeable lipid-based outer membrane. (my bold)-"This outer membrane acts as a defensive barrier against attacks from the human immune system and antibiotic drugs. It allows the pathogenic bacteria to survive, but removing this barrier causes the bacteria to become more vulnerable and die.-***-"'All Gram-negative bacteria have a defensive cell wall. Beta-barrel proteins form the gates of the cell wall for importing nutrition and secreting important biological molecules.-"The beta-barrel assembly machinery (BAM) is responsible for building the gates (beta-barrel proteins) in the cell wall.-"'Stopping the beta-barrel assembly machine from building the gates in the cell wall cause the bacteria to die."
Scientists studied the gram-negative bacteria E.coli, in which the beta-barrel assembly machinery contains five subunits - known as BamA, BamB, BamC, BamD and BamE. They wanted to know exactly how these subunits work together to insert the outer membrane proteins into the outer membrane or cell wall.-"Prof Dong said: "Our research shows the whole beta-barrel assembly machinery structures in two states - the starting and finishing states. We found that the five subunits form a ring structure and work together to perform outer membrane protein insertion using a novel rotation and insertion mechanism.-"'Our work is the first to show the entire BAM complex. It paves the way for developing new-generation drugs.-"'The beta-barrel assembly machinery is absolutely essential for Gram-negative bacteria to survive. The subunit BamA is located in the outer membrane and exposed to the outer side of the bacteria, which provides a great target for new drugs.-"'In Human mitochondria, a similar complex called sorting and assembly machinery complex (SAM) is responsible for building the outer membrane proteins in the outer membrane of mitochondria."-Comment: Again these are automatic protein complex defense mechanisms, not cell thinking. All membranes have a lipid layer. The real issue is the BAM complex. Most E. coli are not dangerous to us.