Molecule of the Month - 2001

The "Molecule of the Month" presents short accounts on selected molecules from the Protein Data Bank. Each installment includes an introduction to the structure and function of the molecule, a discussion of the relevance of the molecule to human health and welfare, and suggestions for how visitors might view representative structures themselves.

Please note, the "Molecule of the Month" is not intended to be a comprehensive index to entries in the PDB, nor necessarily represent the historical record. The structures used to illustrate each installment are chosen at the discretion of the author of the "Molecule of the Month".

When using these images, please be sure to include the proper citation information, which can be found in the Structure Explorer for each PDB file referenced in each installment.

Complete Molecule of the Month Index

Alcohol Dehydrogenase (by D.S. Goodsell)
Jan. 2001

Here's a toast to alcohol dehydrogenase. While recovering from the excesses of New Year's Eve, we might ponder the enzyme that ceaselessly battles the champagne that we consume. Alcohol dehydrogenase is our primary defense against alcohol, a toxic molecule that compromises the function of our nervous system... [MORE...]
Available in PDF Format [266 Kb].

Insulin (by D.S. Goodsell)
Feb. 2001

Our cells communicate using a molecular postal system: the blood is the post office and hormones are the letters. Insulin is one of the most important hormones, carrying messages that describe the amount of sugar that is available from moment to moment in the blood... [MORE...]
Available in PDF Format [150 Kb].

Transfer RNA (by D.S. Goodsell)
Mar. 2001

Since the process of DNA-directed protein synthesis was discovered, scientists and philosophers have searched, more or less seriously, for a relationship between the triplet nucleic acid codons and the chemical nature of the amino acids... [MORE...]
Available in PDF Format [230 Kb].

Aminoacyl-tRNA Synthetases (by D.S. Goodsell)
Apr. 2001

When a ribosome pairs a "CGC" tRNA with "GCG" codon, it expects to find an alanine carried by the tRNA. It has no way of checking; each tRNA is matched with its amino acid long before it reaches the ribosome. The match is made by a collection of remarkable enzymes, the aminoacyl-tRNA synthetases. These enzymes charge each tRNA with the proper amino acid, thus allowing each tRNA to make the proper translation from the genetic code of DNA into the amino acid code of proteins... [MORE...]
Available in PDF Format [445 Kb].

Cyclooxygenase (by D.S. Goodsell)
May 2001

Cyclooxygenase performs the first step in the creation of prostaglandins from a common fatty acid. It adds two oxygen molecules to arachidonic acid, beginning a set of reactions that will ultimately create a host of unusual molecules. Aspirin blocks the binding of arachidonic acid in the cyclooxygenase active site. The normal messages are not delivered, so we don't feel the pain and don't launch an inflammation response... [MORE...]
Available in PDF Format [237 Kb].

Myosin (by D.S. Goodsell)
Jun. 2001

All of the different movements that you are making right now--your fingers on the computer keys, the scanning of your eyes across the screen, the isometric contraction of muscles in your back and abdomen that allow you to sit comfortably--are powered by myosin. Myosin is a molecule-sized muscle that uses chemical energy to perform a deliberate motion... [MORE...]
Available in PDF Format [331 Kb].

Actin (by D.S. Goodsell)
Jul. 2001

The complex ultrastructure of cells--their shape and internal structure--and the many motions of cells are largely supported by filaments of actin. A tangle of cross-linked actin filaments fills the cytoplasm of animal, plant and fungal cells, forming a "cytoskeleton" that gives the cell shape and form and provides a scaffold for organization... [MORE...]
Available in PDF Format [278 Kb].

Poliovirus and Rhinovirus (by D.S. Goodsell)
Aug. 2001

Viruses are biological hijackers. They attack a living cell and force it to make many new viruses, often destroying the cell in the process. Picornaviruses, or "little RNA viruses," are among the most simple viruses. In spite of their simplicity, or perhaps because of it, the picornaviruses are also among the most important viruses for human health and welfare... [MORE...]
Available in PDF Format [440 Kb].

Antibodies (by D.S. Goodsell)
Sep. 2001

Antibodies are our molecular watchdogs, waiting and watching for viruses, bacteria and other unwelcome visitors. Antibodies circulate in the blood, scrutinizing every object that they touch. When they find an unfamiliar, foreign object, they bind tightly to its surface... [MORE...]
Available in PDF Format [363 Kb].

Photosystem I (by D.S. Goodsell)
Oct. 2001

Look around. Just about everywhere that you go, you will see something green. Plants cover the Earth, and their smaller cousins, algae and photosynthetic bacteria, can be found in nearly every corner. Everywhere, they are busy converting carbon dioxide into sugar, creating living organic molecules out of air using the energy of sunlight as power. This process, termed photosynthesis, provides the material foundation on which all life rests... [MORE...]
Available in PDF Format [580 Kb].

DNA (by D.S. Goodsell)
Nov. 2001

Each of the cells in your body carries about 1.5 gigabytes of genetic information, an amount of information that would fill two CD-ROMs or a small hard disk drive. Surprisingly, when placed in an appropriate egg cell, this amount of information is enough to build an entire living, breathing, thinking human being... [MORE...]
Available in PDF Format [324 Kb].

Glycogen Phosphorylase (by D.S. Goodsell)
Dec. 2001

Although it may not seem so during the holiday season, we do not have to eat continually throughout the day. Our cells do require a constant supply of sugars and other nourishment, but fortunately our bodies contain a mechanism for storing sugar during meals and then metering it out for the rest of the day. The sugars are stored in glycogen, a large molecule that contains up to 10,000 glucose molecules connected in a dense ball of branching chains. Sugar is released from glycogen by the enzyme glycogen phosphorylase... [MORE...]
Available in PDF Format [365 Kb].