You come across a membrane protein that has been determined to be involved with

Question

You come across a membrane protein that has been determined to be involved with the passive transport process.
A gene has been identified for the protein however you are unable to develop any structural information about this protein by crystallography, CD or NMR.

1. Of the two types of structures that are associated with membrane proteins, which would you presume is most associated with this process and why?



2. Since a structure cannot be determine by the methods above, use the primary sequence of the protein to describe an approach that can be used to confirm or deny that hypothesis.



3. Describe two challenges that are associated with membrane proteins which make the structural studies difficult.

Explanation / Answer

Of the two types of structures that are associated with membrane proteins, which would you presume is most associated with this process and why? Integral membrane proteins can be classified as "transmembrane proteins," that span across the membrane which is the likely way to open a channel. THey could conceivably just bind to the substance and facilitate passive transort, but more likely they form a channel and they are spanning the entire membrane. 2. Since a structure cannot be determine by the methods above, use the primary sequence of the protein to describe an approach that can be used to confirm or deny that hypothesis. The primary structure refers to the sequence of the different amino acids of the peptide or protein. Post-translational modifications such as disulfide formation, phosphorylations and glycosylations are usually also considered a part of the primary structure, and we would look for both lipophilic an lipophobic amino acids because the proteiin has to have domains with both types. 3. Describe two challenges that are associated with membrane proteins which make the structural studies difficult. One is that we must use detergents to remove the protein from the membrane and we can destroy or alter it. Also it is likely to be big. X-ray crystallography and Nuclear Magnetic Resonanc eare optioons. As the protein becomes larger and more complex, the atomic-level picture provided by X-ray crystallography becomes less well-resolved however, X-ray crystallography may be possible even for proteins with thousands of atoms. In NMR we are limited to relatively small proteins or protein domains especially since in large proteins the magnetization relaxes faster, causes the peaks to become broader and weaker.

Related Questions

Navigate

• Browse (All)
• Browse Y
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.