Part of the RCSB-Rutgers Open House (described in this newsletter's Message from the RCSB PDB) was a celebration marking the opening of the Molecular Art Mural. Painted by local artist Jessica Milazzo onto the walls of RCSB-Rutgers, this mural depicts some of the earliest structures solved by X-ray crystallography.The mural's accompanying text notes, reprinted here, are from the RCSB PDB's Molecule of the Month series and RCSB PDB staff.

Lysozyme

Lysozyme protects biological organisms from the ever-present danger of bacterial infection. This small enzyme attacks the protective cell walls of bacteria. Bacteria build a tough skin of carbohydrate chains to brace their delicate cell membranes against changes in osmotic pressure. Lysozyme breaks these carbohydrate chains, which destroys the structural integrity of the bacterial cell wall. The bacteria then burst under their own internal pressure.

Lysozyme is present in many places that are rich with potential food for bacterial growth. The lysozyme pictured here is from hen egg white, where lysozyme serves to protect the proteins and fats that will nourish the developing chick.

Lysozyme was the first enzyme structure solved.

PDB ID: 2lyz. Blake, CCF, Koenig, DF, Mair, GA, North, ACT, Phillips, DC and Sarma, VR (1965) Structure of hen egg-white lysozyme. A three dimensional Fourier synthesis at 2 Angstrom resolution. Nature, 206, 757-761. Blake, CCF, Johnson, LN, Mair, GA, North, ACT, Phillips, DC and Sarma, VR (1967) Crystallographic studies of the activity of hen egg-white lysozyme. Proc. R. Soc. London Ser. B, 167, 378-388.

Myoglobin

Myoglobin was the first reported protein structure. It represented a milestone in structural biology for which John Kendrew shared the Nobel Prize in Chemistry in 1962. This structure, along with the work on hemoglobin being carried out by Max Perutz, set the stage for developing our emerging understanding of biology at the atomic level.

Myoglobin is a small, bright red protein. It is very common in muscle cells, and gives meat much of its red color. Its biological function is to store oxygen obtained from hemoglobin that is carried in the blood for use when muscles are hard at work. The myoglobin used in the structure shown was taken from sperm whale muscles. Marine whales and dolphins have a great need for myoglobin, so that they can store extra oxygen for use in their deep dives undersea.

PDB ID: 1mbn. Kendrew, JC, Bodo, G, Dintzis, HM, Parrish, RG and Wyckoff, H (1958) A three-dimensional model of the myoglobin molecule obtained by X-ray analysis. Nature, 181, 662-666. Watson, HC (1969) The stereochemistry of the protein myoglobin. Prog. Stereochem., 4, 299.

Ribonuclease

The structure of ribonuclease was the third protein - after myoglobin and lysozyme - that was determined by X-ray crystallography. Two independent ribonuclease structures were reported in 1967.

Ribonucleases are small enzymes that catalyze the breakdown of single-stranded ribonucleic acid (RNA) by cleaving a phosphodiester bond. Ribonucleases have many biological functions, such as cutting harmful RNA into smaller components in order to remove them from the cell. Ribonuclease's structure contains a cleft in which the RNA is held during cleavage.

Kartha, G, Bello, J and Harker, D (1967) Tertiary structure of ribonuclease. Nature, 213, 862-865. Wyckoff, HW, Hardman, KD, Allewell, NM, Inagami, T, Tsernoglou, D, Johnson, LN and Richards, FM (1967) The structure of ribonuclease-S at 6 Angstrom resolution. J. Biol. Chem., 242, 3749-3753.

Hemoglobin

The science of protein structure began with the structure of hemoglobin. After years of arduous work, Max Perutz and his coworkers determined its atomic structure. Perutz's pioneering work in X-ray crystallography of proteins - including his study of hemoglobin - won him the Nobel Prize in 1962.

Hemoglobin is the protein that makes blood red. It is composed of four protein chains - two alpha chains and two beta chains, each with a ring-like heme group containing an iron atom. Oxygen binds reversibly to these iron atoms and is transported through blood. Each of the protein chains is similar in structure to myoglobin, the protein used to store oxygen in muscles and other tissues.

PDB ID: 2dhb. Bolton, W and Perutz, MF (1970) Three-dimensional Fourier synthesis of horse deoxyhaemoglobin at 2.8 Angstrom units resolution. Nature, 228, 551-552. Perutz, MF, Rossmann, MG, Cullis, AF, Muirhead, G and Will, G (1960) Structure of haemoglobin: a three-dimensional Fourier synthesis at 5.5 Angstrom resolution. Nature, 185, 416-422.