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Up ahead, I spotted a bench facing the river. There was a lovely, large maple tree rising behind the bench which seemed to lend a sense of protected seclusion to the area. In addition, there was a light standard near one end of the bench bathing the spot with a soft light that lent a very appealing quality to the area.

Apparently, Jennifer was drawn to the site as well. She said: "I imagine you are probably exhausted from all the spiritual excitement that's been going on. Would you like to rest your weary soul, or whatever, on yonder bench for a little while?"

"I am not worthy of your kind solicitations," I offered.

"You're right," she agreed, "you aren't worthy, but why don't we sit down in any case. Furthermore, I wasn't soliciting. I was suggesting."

We walked the short distance to the bench in silence and sat down. A slight, intermittent breeze was coming off the water and rustled lightly through the leaves of the maple behind us.

Although the number of people walking along the river had thinned out a little, there still were a few who, from time to time, passed near our bench area- singly, in pairs, and, occasionally, in groups of three or four. In between the time of the passers-by, one could hear the water making contact with various rocks and other obstacles near the bank of the river.

After some minutes had passed in silence, while we each were absorbing the atmosphere that surrounded us, I said: "In some of my more idle moments, I have devised what I call the protein theory of relationships. Would you like to hear about it?" I inquired.

"Does it have a happy ending?" Jennifer asked.

"Well," I said, "the theory is kind of post-structuralist in its ambience, so I'm not sure there is any ending to it, just a series of perspectives."

Jennifer repeated the name: 'protein theory of relationships', several times. "Hmmm," she murmured. "This sounds very reductionistic to me, David."

"Not at all," I countered. "It's intended to be metaphorical."

Jennifer sighed: "I hope I'm not going to regret giving you the go-ahead on this."

"You probably will regret it," I conceded, "but just try not to choke too much on the bitter pill that fate is forcing you to swallow...the choking sound will disturb my concentration."

Jennifer made an exaggerated rolling, circular motion with her hand. With, what I hoped was, feigned impatience and irritation, she was imploring me to get going and try to speed things along.

"Very well," I said, "since the consensus of those in attendance seems to be overwhelmingly in favor of proceeding on, here follows the tale, in several acts, of the protein theory of relationships. Quiet please, and, kids, do not attempt this at home."

"Some might say it should not even be attempted here," Jennifer heckled.

Attempting to ignore her comment, I began my account with an imperious air. "As any little studious girl or boy knows, proteins are made up of a sequence of some twenty-plus amino acids."

"Moreover, every amino involves three aspects. There is a carboxyl group that consists of a carbon atom, two oxygen atoms and an atom of hydrogen. In addition, there is an alpha-amino group consisting of two hydrogen atoms bonded with an atom of nitrogen. Both the carboxyl and the alpha-amino groups are always the same from one amino acid to the next.

"There is also a third part of an amino acid which differs from amino acid to amino acid. This third part is what gives any given amino acid its special or particular characteristics.

"The simplest example of this third component is glycine that has a single hydrogen atom, in addition to the carboxyl and alpha-amino groups which glycine holds in common with other amino acids. The third component of each of the other twenty-odd amino acids differs not only from glycine's hydrogen atom, but from one another as well .

"Chains of amino acids are held together through covalent bonding in which various electrons are shared among some of the atoms of neighboring amino acids. These chains are known as polypeptides.

"The specific sequence of the different amino acids that form the polypeptide backbone are known as the primary structure of a protein. Each protein has a unique sequence of amino acids and, therefore, a unique primary structure.

"These polypeptide chains tend to have twisted, multi-dimensional personalities. In other words, they prefer not to remain straight and uni-dimensional. They like to fold up into three-dimensional structures. This three-dimensional form is known as the tertiary structure of a protein.

"The pattern of folding depends on the way positively and negatively charged molecular groups are distributed along the polypeptide chain. Some parts of this chain of amino acids are attracted to other portions of the same chain, and some parts of this chain are repelled by other sections of that chain."

Jennifer held up a hand, indicating her desire for a temporary halt to my account. "What happened to the secondary structure part of this story?" she asked. "We seemed to have shifted from primary to tertiary, with nary a word about what comes in between."

Responding to her with the impatient manner with which a side-show carnival barker might deal with someone who was trying to poke holes in the spiel, I said: "If the young lady would be patient, all will be revealed in its proper time.

"Now," I mumbled, "where was I before being so rudely interrupted." I made an eureka sort of face, as if discovering something, and started in again on unpacking the intricacies of the protein theory of relationships.

"When everyone gets done folding around, the polypeptide chain of a given protein has a unique three-dimensional shape. No two kinds of protein have precisely the same shape, although, sometimes, two different kinds of proteins may have similar three-dimensional folding patterns, either as a whole, or, more importantly, in part.

"Now, the primary and tertiary structures of a given protein have a lot to do with what kinds of processes such a protein can participate in or with what sorts of function the protein can have. For example, because of these primary and tertiary structural features, some proteins serve as enzymes that help various biochemical reactions take place. Enzymes are catalysts.

"Other proteins, because of different primary and tertiary structural features, serve as building blocks for the various parts of a cell. These building blocks are referred to as structural proteins.

"Enzyme proteins and structural proteins depend on one another in various ways. Neither one is worth much on its own. Moreover, these two kinds of molecule, together with a few others types of molecules such as DNA, RNA, lipids, and carbohydrates, help give expression to the complex forms and processes which characterize a living organism.

"Both enzyme proteins and structural proteins depend on their primary structures and their tertiary structures to accomplish their respective tasks. If an enzyme, for example, has the 'wrong' kind of shape for a given situation, then biochemical processes cannot take place quickly enough, if at all, to be able to help sustain life. On the other hand, if a structural protein has the 'wrong' structural properties for a given situation, then the form of an organelle, cell, tissue, organ or organism will be defective in some fashion.

"This issue of correct shape becomes especially important when one is considering certain kinds of intracellular and intercellular forms of communication. As I am quite confident our very intelligent audience knows, there are different kinds of protein receptors embedded in the surface of the membranes of cells. Only biological agents, such as other proteins, with the right shape or pattern of folding, will be able to activate such membrane receptors.

"When do we get to the metaphorical part?" Jennifer inquired.

"Your wish is my command." I responded.

"I wish we could move onto something else," she indicated with an amused expression.

"Wrong wish," I told her. "Besides, you feet shufflers in the audience will be happy to know that, yes, indeed, we have arrived at the magical moment of transition to the realm of metaphor."

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