Question

This question is related to Biophysical Chemistry-College level

Luciferase is a protein that produces light. It is responsible for the glow of fireflies, for example, but also for the bioluminiscence of Florida's space coast and Indian River in the summer. The wonderful chemistry behind this protein is briefly explained on the protein data bank (http://www.rcsb.org/pdb/101/motm.do?momID=78) and in more detail on wikipedia (http://en.wikipedia.org/wiki/Luciferase).

Here we will look at the structure of a bacterial luciferase, pdb entry 1LUC; use VMD (on your own computer) to answer the following questions.

A. Describe the structure of the protein. How many chains are there? What is the fold (shape) of the protein? Are there any disulfide bonds?

B. What kind(s) of helices does the protein have?

C. Explain whether one would expect helix α9 of chain B (i.e. residues 260270 of chain B) to be amphipathic or not. Then, check to see whether it is amphipathic or not.  

D. Are there any cis peptide bonds? If so, give the chain and residue names + numbers.

E. Are there any prosthetic groups? If so, give the name of those groups.

Answer 1

A. Bacterial Lucifer's is a heterodimer . Both subuni contain a single alfa subunit (355 AMINO ACIDS)with 8 parallel beta sheet and 8 agla helix and another subunit beta(321AMINO ACIDS) cantain 8 afla helix and 8 parallel beta sheets

There is alfa beta barrel structure is given for each subunit and substrate is shared by each sub unit

There substrate is FMN ,FMNH2 in presence of oxygen interact with cysteine 106 .

I did not find any disulfide bond in the litrature

B. Alfa helixs.

D.in each subunit contain cis prolin 160

E.mg2+ and FMN ,FMNH2 are the prothatic groups which bind to active stie of protein