Question

Which level of protein structure is disrupted by allosteric inhibition?

A. Primary

B. Secondary

C. Tertiary

D. Quaternary

Answer 1

Quaternary level of protein structure is disrupted by allosteric inhibition.

Allosteric inhibition : When an allosteric inhibitor binds to the allosteric site of an organism, it changes the conformation or structure of the active sites of an enzyme so that the enzyme can't binds to their substrate and becomes inactive. In the allosteric inhibition as there are many binding sites are present in an enzyme, the binding of allosteric inhibitor to one site changes the structure of other binding sites and hence decreasing the ability of the enzyme to function.

It is here to be noted that enzymes are nothing but the complex proteins.

The quaternary level of proteins are nothing but the proteins which consists of multiple folded protein subunits which are binds to one another by non-covalent forces. These quaternary proteins are also known as holoenzyme whose subunits are different from one another in their structure and function. Some subunits are called as regulatory subunits, the core part is known as catalytic subunits while the all other assemblies also contains quaternary structure. The change in the quaternary structure of individual subunits or all subunits changes the conformation of the active sites of the enzyme and makes the enzyme inactive and this effect or process is known as allostery. Sometimes allostery also regulates the physiological function of the enzyme actively.

Also evidence is there that Quaternary structure is an essential component which contributes to the allosteric regulation mechanism (which may be caters to the activation or inhibition) in a key enzyme from the bacterium Mycobacterium tuberculosis.

Hence from all the above discussion we can conclude that during allosteric inhibition the quatenary level structure of protein gets disrupted.