TIM barrel question

[Nemisisnik]

I am working on homework and i had a question about the TIM barrel which i will post here:

The high-resolution crystal structure of TIM - posphoglycohydroxamate complex revealed a 10 residue loop, which closes over the enzyme active site in the TIM barrel once the posphoglycohydroxamate binds to the active site. posphoglycohydroxamate binds tightly to TIM. Explain why. In the enzyme alone structure, the loop is flipped up like a hinged lid. A deletion of this loop has no effect on the integrity of the TIM fold. However, a small molecule of methylglyoxal (CH3-CO-CH=O) is detected as a product. Provide an explanation for the formation of methyglyoxal by the mutant TIM. also explain why the wild-type TIM methylglyoxal is not formed as the product (Hint: consider stereoelectronic control of the chemical reaction).

 

I think that the first part he just means that it bind tightly so that it can act as an incduced fit enzyme and the conformation will change to close and keep the substrate in and for the second part i dont even know where to start, seeing as we have not done anything about this in class.

 

Please help, the best you can, thank you!