Correct Answer: A
Explanation:
Researchers have uncovered molecular details of how pathogenic bacteria fight back against the human immune response to infection.
Scientists at the University of East Anglia (UEA) and Institut de Biologie Structurale (CEA-CNRS-UGA, France) have identified the structure of NsrR.
This is a bacterial protein that binds to DNA and plays a key role in the bacterium’s resistance to nitric oxide (NO), which is produced in the initial immune response to infection.
In order to counter the effects of NO, which can be toxic to living organisms, many bacteria have evolved ways to detect it and mount a cellular response.
The most common dedicated NO sensor in bacteria is the regulatory protein NsrR. Regulatory proteins bind to DNA, and in doing so control whether particular genes are switched on or off.