Please show your steps and explain your thought process Than

1. (5 points) crocodiles have much lower concentrations of myoglobin compared with other diving mammals. How do they stay under water for so long?? Explain with 30 words or less. 2. gene, FUT-1, a responsible for Lfucose to create the H-antigen, which is the base structure of A, B and O types. A few people (including Alan Quartermane!) have a mutation in this gene, and thus have no blood-type. Show the betaform of L-fucose--the critical linker for the blood group types! Note: Reference sheets attached 3. (5 points Beta-sheets are the second most common secondary structural element. The major secondary structural element in flavodoxin (Tm -67 deg. C) is parallel beta-sheets while in pyruvate kinase CTm 90 deg. the major secondary structural element is antiparallel beta sheets. Which protein is more stable? Explain. Full credit is given for an explanation for astructural reason for these differences (beyond the obvious!).

Solution

A parallel arrangement of beta sheets is always less stable than antiparallel arrangement. This is because in parallel arrangement, the N-termini of one beta strand will be in front of the N-terminus of second beta-strand. This means that two similar amino acids will be present side by side. So, there is repulsion between two amino acids. As a result, the hydrogen bonds between two strands will become longer; finally making the overall structure weak.

Also, a less stable protein will always melt at lower temperature than a more stable protein. So, by looking at the Tm values of the two proteins, it is evident that flavodoxin, that is having parallel arrangement of beta sheets is less stable than pyruvate kinase.