Nitrogen-Containing Compounds - Natural Products Chemistry: Sources, Separations, and Structures - page 79

A dependent DNA polymerase enzyme, known as a reverse transcriptase, is able
to transcribe a single-stranded RNA sequence into double-stranded DNA. Such
enzymes are found in all cells and are an essential component of retroviruses. These
require RNA replication of their genomes. It should be noted that direct translation
of DNA information into protein synthesis has not yet been observed in a living
organism. Finally, proteins appear to be an informational dead end and do not pro-
vide a structural blueprint for either RNA or DNA. Structural information transla-
tion is always from mRNA to protein.

SUMMARY
This chapter introduces the nitrogen-containing molecules: proteins, peptides, and
amino acids (the building blocks and precursors to linear peptides and some cyclic
peptides). The chapter continues with the nucleic acids and their bases, followed by
examples of alkaloids. The amino acids tryptophan, phenylalanine, and tyrosine are
shown as important precursor building blocks for alkaloids.

QUESTIONS

1. Give chemical structures of the following alkaloids: atropine, nicotine, and
morphine.

2. Give the structures of the following:

a. Caffeine, theobromine, and theophylline

b. Mescaline, adrenaline, and ephedrine

c. Putrescine, spermidine, and spermine

d. One example of a cyclopeptide alkaloid

e. One example of a terpene-like alkaloid

f. One example of a steroid-like alkaloid

FURTHER READING

p roteinS
C. I. Brändén and J. Tooze. 1999. Introduction to Protein Structure . Garland Pub.
A. Kessel and N. Ben-Tal. 2012. Introduction to Proteins: Structure, Function, and Motion.
Taylor & Francis.

a lkaloidS
E. Fattorusso and O. Taglialatela-Scafati. 2008. Modern Alkaloids: Structure, Isolation, Synthesis,
and Biology . Wiley.
M. Hesse. 2002. Alkaloids: Nature's Curse or Blessing? Wiley.

n uCleiC a CidS
V. A. Bloomfield, D. M. Crothers, and I. Tinoco. 2000. Nucleic Acids: Structures, Properties,
and Functions . University Science Books.
P. O. P. Ts'o. 2012. Basic Principles in Nucleic Acid Chemistry . Elsevier Science.