Archive of Molecular Highlights

Summer 2005

Ubiquitin (Ub) is a 76 residue, highly conserved protein found in all eukaryotic organisms. Ubiquitin itself does not perform any catalytic, transportative, or structural function. Rather, it is a signalling mechanism where some other regulatory mechanism will use it to label a target protein for a particular fate. It is best known for its role in ATP dependent protein degradation.

Ubiquitin ribbon diagram

Spring 2006

Calmodulin (CaM) is one of the best known examples calcium binding regulatory proteins in intracellular signalling pathways. Like Ubiquitin, it is highly conserved and abundant in all eukaryotic cells. As a signalling protein, Calmodulin's function is to bind calcium ions and then bind a target protein, affecting its activity. It affects processes ranging from neurotransmitter release to membrane protein organization.

Calmodulin ribbon diagram

Summer 2006

Lysozyme (Lys) is an enzyme that plays an important role in the prevention of bacterial infections. It does this by attacking a specific component of certain bacterial cell walls, peptidoglycan. It was discovered by Alexander Fleming in 1921 when he demonstrated that his own nasal mucus had the ability to inhibit the growth of a certain strain of bacteria in culture. In 1966, David Chilton Phillips, using x-ray crystallography, determined lysozyme's structure, the first ever solved for an enzyme. It has been an important experimental model ever since.

Lysozyme ribbon diagram

Fall 2008

Dihydrofolate Reductase (DHFR) is a very important enzyme because it produces cofactors that are necessary for DNA synthesis. Specifically, DHFR catalyzes the reduction of folate and 7,8-dihydrofolate (DHF) to 5,6,7,8-tetrahydrofolate (THF). THF is an essential cofactor involved in the the transfer of methyl, methylene, and formyl groups from one molecule to another during the production of nucleotides and several amino acids. An important example of this is the utilization of carbon units from a THF cofactor by thymidylate synthase to make thymidine nucleotides.

DHFR ribbon diagram