1. Answer to first pic is A. Questions below relate to it.
You are studying an enzyme that localizes to the plasma membrane with a known biological
activity of converting a colorless cytosolic chemical into a deep red pigment that accumulates in
the cytosol. Your work has indicated that both the colorless compound and deep red product are
positively charged and that there are no transporters for either of these compounds. After cloning
the gene encoding your protein, you submit the protein sequence to one computer algorithm and
get the following prediction: The black rectangles indicate predicted transmembrane domains
(TMDs), and the hatched box indicates the active enzymatic domain, which itself folds into an
independent domain that contains amino acids with entirely hydrophilic side chains. If this
topological preciction is correct, which of the diagrams below depicts the orientation of the
protein when inserted into the lipid bilayer of the endopmen reticulum after its synthesis?
Explain why the answer you chose is correct, including a molecular mechanism for this
orientation.
Considering the exact same protein from the previous question, which of the following images
represents the final orientation of this protein after it is transported to t plasma membrane?
Explain why the answer you chose is correct, including a molecular mechanism for this
orientation.
2 points With respect to the previous two questions, does the original topological prediction
about the structure of this protein make sense with respect to the known biological activity of the
protein? Explain why or why not in three sentences or less.