Problem:
We know that each methylene(-CH2) or methyl (CH3-) grouo in a straight chain hydrocarbon extends the chain lenght by~0.13nm. We also know from stdies of protein strcuture that one turn of an alphaheilx includes 3.6 amino aacid residues and extends the long axis of the helix by ~0.56nm.
Required:
Question 1: How long is a single molecule of areachidate in its fully exended form( do not include the carbonyl carbon in your calculation)?
Question 2: Approximately how many amino acids must a helical transmembrane segment of an integral membrane protein have if the segment is to span the lipid bilayer defined by two arachidate molecules laid end to end?
Question 3: The protein bacteriorhopsin has 248 amino acids and seven transmembrane segments. Using the value calculated for 1B above, estimate the overall percentage of the amino acids that are part of the transmembrane segments in this protein?
Could someone help to explain the answer of these questions.