Chem 335 - Winter 2000
Organic Chemistry II
Dr. Carl C. Wamser

Molecule of the Week #8

Queuine

Hi Dr. Wamser! I just wanted to take a guess at the molecule. I think that it is queuine. Queuine is a "hypermodified base found at the wobble position of tRNAs specific for Asn, Asp, His, and Tyr". Prokaryotes have the ability to synthesize this molecule, but it is a nutrient for eucaryotes. It is known to stop codon readthrough in TMV RNA, and it has been proposed that it deters frameshifts in mammalian retroviruses. It is also known to reduce pathogenicity in Shigella bacteria by causing low translation of mRNA.
-April Hunter

Sources:
www.chemfinder.com
www.embl-heidelberg.de

Since no one has solved the molecule for week #8 and it is soon to be week #10 I thought I'd give it a try. I imagine everyone is too busy studying for exams. I'm not in the class so I had the leisure to spend a few minutes deciphering the molecular formula. I think the molecule is queuine, C12H15N5O3. I couldn't find much information on quenine except that it is a "complex purine-like compound chemically related to the nucleic acid base guanine." It is found either in the cytoplasm or in the anticodon of certain transfer RNAs. Research has shown that mammals, insects, fish and probably all eukaryotes cannot synthesize queuine, rather it must be obtained from their diet or it can be provided by intestinal microflora.

Sources: chemfinder.com and bio.utk.edu/ecology/faculty/farkas.html

Suzi Buchanan

The molecule of the week is Queuine. It's molecular formula is C12H15N5O3.
"Queuine is a complex purine-like compound chemically related to the nucleic acid base guanine. It occurs free in the cytoplasm or is found in the first position of the anticodon of certain transfer RNAs. The molecular basis for understanding how the combined deficiency of tyrosine and queuine leads to these physiological and behavioral abnormalities is my major research effort." Walter R. Farkas Ph.D., 1960, Duke University.

~Dustin Nouri

The name of the molecule is QUEUINE.

Queuine is a hypermodified base found at the wobble position of tRNAs specific for Asn, Asp, His and Tyr, in most organisms with the exception of yeast and archeabacteria. Queuine is synthetized de novo in procaryotes but is a nutrient for eucaryotes.

Nicole A. Hannah

Editor's note - queuine, which is known as queuosine when it is attached to ribose in readiness for incorporation into RNA, is a major topic of research at Portland State University in the laboratories of Professor Dirk Iwata-Reuyl.