Question

Question 7 What is the strongest noncovalent interaction (intermolecular force) present in each of the labeled protein-chromophore pieces? HH HC start Hoc HN H HHCN 1 SI I 7 H NI HC-C-C=0 | CH, H ) 4N/ A, Q 7 căCH, C-CH HN Heç I O= C HC -H H CH₂ díl H6 CH – CH₃ CH2 FH CH-CH Hc- C =0" He CH₂ (CH₂ CH2 CH₂ H₃C) CH2 cc Sec O=C end NH2 C- C H2H2 HNS HNG Hayden-McNeil, LLC Figure 6-1. Protein-chromophore structure in Spirulina.! 3,4 Table 6-1. Key for protein-chromophore structure. Parts of Structure Chromophore Water Most protein atoms Color and Text Coding Bold, black Bold, black Black type and lines

Answer 1

A. Here the intermolecular interaction is between two polar carbonyl groups. Thus, it is majorly dipole-dipole interaction.

B. Here the interaction is between a cationic part (-NH3+) and anionic part (-COO-), so, majorly ionic interaction is there. Also interaction between N-H hydrogens (H-bond donor) and carboxylate oxygens (H-bond acceptor) are present. But the major contributor is the ionic interaction.

C. Here the interaction involves O-H (as H-bond donor) and C=O (as H-bond acceptor), so the major interaction involved is H-bonding.

D. Here we have interaction of N-H (H-bond donor) proton, with O from H2O (H-bond acceptor). So, the interaction is H-bonding.

E. Here we have interaction of N-H (H-bond donor) proton, with N from cycle (H-bond acceptor). So, the interaction is H-bonding.

F. The interaction involves two non-polar -CH3 groups, thus, here induced dipole-induced dipole interaction or London interaction is the major one