bacterial intelligence using molecular switch (Animals)

by David Turell @, Friday, October 13, 2017, 21:57 (621 days ago) @ David Turell

Riboswitches on mRNA can change gene expression:

"Many bacteria have molecular control elements via which they can switch genes on and off. These riboswitches also open up new options in the development of antibiotics or the detection and decomposition of environmental toxins.


"Riboswitches are located on the messenger ribonucleic acid (mRNA) that transports genetic information to the site of protein biosynthesis. A riboswitch consists of a sensor measuring the concentration of a small metabolic molecule and an effector controlling gene expression and, hence, synthesis of a protein. (my bold)


"The research groups of Professor Gerd Ulrich Nienhaus of KIT and Professor Andres Jäschke of Heidelberg University studied the S-adenosyl-L-methionine (SAM)-I riboswitch. "Attachment of the SAM molecule to this riboswitch causes the conformation, that is the spatial arrangement of atoms, to change from the anti-terminator (AT) to the terminator (T) structure," Nienhaus explains. "As a result, gene expression is switched off."


"In their analysis, the researchers distinguished two conformations (T and AT) of the SAM-I riboswitch, and a total of four conformations (T1, T2, AT1, and AT2). Surprisingly, the riboswitch did not fully switch between the T and AT structures in the presence and absence of SAM, as had been expected, but fluctuated permanently between all states—only weightings were shifted. A result important to the biological function was that structure fluctuations observed with an attached SAM were far quicker than without SAM. As the riboswitch sequence on the messenger RNA is located directly in front of the gene to be controlled, the RNA molecule has to form a T structure (switch off) as quickly as possible after synthesis in the presence of SAM in order to prevent subsequent transcription of the gene to be controlled. Acceleration of structure fluctuations by SAM attachment thus ensures sufficiently quick formation of a T structure. "Consequently, dynamics of the SAM-I riboswitch play an important role for its function," Nienhaus says."

Comment: Note my bold. The riboswitch has a sensor which is following protein levels. It senses and automatically acts. This is the 'intelligence' a bacteria exhibits. All comes from intelligent design and planned instructions.

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