Question 5 The figure below shows GDP in the binding pocket of a G protein. o|P|O HO OHOH y r HNN→C=NH O Arg Glu a) Circle the strongest interaction that exists between i)the side chain of Lys and the phosphate group of GDP van der waals covalent hydrogen bond lonIc ) the side chain of Glu and the ribose group of GDp van der waals covalent hydrogen bond Ionic ii)the side chain of Tyr and the guanine base of gDp van der waals covalent hydrogen bond ionIc b) You make mutations in the gDp-binding pocket of the g protein and examine their effects on the binding of GDP. Consider the size and the nature(e. g charge, polarity, hydrophilicity, hydrophobicity) of the amino acid side chains andand give the most likely reason why each mutation has the stated effect. Consider each mutation independently i)Arg is mutated to a Lys, resulting in a G protein that still binds GDP ii)Asp is mutated to a Tyr, resulting in a G protein that cannot bind GDP. Spring 2004 Final exam practiceSpring 2004 Final Exam Practice 8 Question 5 The figure below shows GDP in the binding pocket of a G protein. NH NH H N C NH C O C O HO Lys Arg Asp Glu Tyr 3 + 2 2 + P P O O O O O OH OH N N NH NH N O CH 2 O- O￾O- 2 O- O - a) Circle the strongest interaction that exists between: i) the side chain of Lys and the phosphate group of GDP van der Waals covalent hydrogen bond ionic ii) the side chain of Glu and the ribose group of GDP van der Waals covalent hydrogen bond ionic iii) the side chain of Tyr and the guanine base of GDP van der Waals covalent hydrogen bond ionic b) You make mutations in the GDP-binding pocket of the G protein and examine their effects on the binding of GDP. Consider the size and the nature (e.g. charge, polarity, hydrophilicity, hydrophobicity) of the amino acid side chains and and give the most likely reason why each mutation has the stated effect. Consider each mutation independently. i) Arg is mutated to a Lys, resulting in a G protein that still binds GDP. ii) Asp is mutated to a Tyr, resulting in a G protein that cannot bind GDP