Answer

Scientific Article Analysis

Summary

            Everts’ (2013) article titled Mirror Molecule and published in the Scientific American Journal is a brief but an insightful article on the nature’s use of both L-amino acids and D-amino acids. L-amino acids are largely utilized by higher organisms such as human while D-amino acids have been largely associated with single-celled organisms; particularly bacteria (Everts, 2013). In evolutionary terms, the first chemical entities were made from L-amino acids since they were able to replicate themselves and it resulted in natural bias of use of L-amino acids. Right-handed amino acids have been for a long time thought as having minimal roles in higher organisms since they would be mismatched and are dysfunctional. In her article, Averts (2013) shades some new insights that even larger organisms such as humans, rats, platypus, tree frog, and lobsters have useful biological and physiological functions of D-isomers. In humans, D-aspartate has been demonstrated as a neurotransmitter necessary in normal development of the brain. Besides, D-serine associates with L-glutamate so as to co-activate neuronal molecules, which are essential for neuronal synaptic plasticity (Everts, 2013).  Platypus from a poison synthesized using D-amino acids. The painful poison released from the platypus sharp can stagger male competitors. Besides, the poison acts as an effective defense mechanism against troublesome dogs and humans. Rats have been found to harbor high concentration of D-alanine in their insulin-secreting β-cells of their pancreases.  A tree frog known as Phyllomedusa bicolor produces a potent hallucinogen made of D-amino acids, perhaps as a defensive mechanism against predators (Everts, 2013).  Lobsters use D-amino acids for romance purposes and for keeping salt levels in order.  Unlike the commonly held belief, right-handed amino acid molecules have important roles in human physiology and they hold a significant potential of being used in the development of novel therapeutics. Right-handed amino acids have a potential of being used in management of chronic conditions such as schizophrenia, cystic fibrosis, and macular degeneration (Everts, 2013).

Relevance to the Course Content

            The article consistently states amino acids are the individual building blocks of proteins. The article is relevant to the course content. In the course, I had learnt that L-amino acids are natural proteins that form part of the human body. Consistently, the article state that all amino acids are referred to as stereoisomers; except glycine, as explained in the course. I have also learnt in the course content that the key difference between D and L isomers is only due the different in the alignment of the molecules alignment in space. Otherwise, D and L isomers have similar molecular mass, density, and number individual elements. Stereoisomerism implies that amino acids (with exception to glycine) tend to exist as mirror images (L and D forms) images of each other. Despite the fact that L and D isomers are mirror images of each other, they cannot be interchangeable or superimposed into each other just like the left and the right human hand. However, the article contravenes what had been taught in the course that only L-forms forms proteins in the human body since it demonstrates the fact that some of the D-amino acids have important roles in the human physiology and anatomy; lack of specific amino acids such as D-serine may lead to chronic conditions such as schizophrenia. Utilization of D-amino acids in the human body seem to break the first rule of mammalian biology that L-amino acids forms the building blocks  of the mammalian protein (Everts, 2013). In addition, the article in consistent with the course content that D-amino acids are found in bacteria (Everts, 2013).

Personal View

            The article has expanded my biology knowledge; particularly on the biological uses and presence of L-amino acids and D-amino acids. Before reading the article, I had a strict rule in mind that only L-amino acids forms proteins in higher organisms such as humans. However, it is interesting to get to know that various D-amino acids have important roles in the human body as well as in other higher organism. In this regard, I have developed an interest to search and read articles that can help expand my knowledge on biological significance of D-amino acids. I have seen potential future research topics on the use of D-amino acids to manage mental health disorders such as schizophrenia as described by Everts (2013). It is surprising to learn that platypus and tree venoms are basically made up of D-amino acids. Since L-amino acids are referred as natural-occurring amino acids; I also suggest that D-amino acids should also be referred as naturally-occurring amino acids since even if they are made from L-amino acids in the human body, they are naturally found in bacteria. One of the questions that I have after reading the article is whether it would be safe to develop antibacterial drugs targeting D-amino acids? The other question that how does proteins made up using D-amino acids act as venoms in the human body yet the body uses some D-amino acids for important anatomic and physiological functions?