Identification of the components of the eukaryotic queuine transglycosylase complex and the effect of its substrate queuine on metabolism

Abstract

Queuine is a 7-deazaguanine derivative of guanine, which replaces guanine in position 34 of the anticodon loop of the transfer RNA for the amino acids, asparagine, aspartic acid, histidine and tyrosine. This base or related analogues are found within eukaryotes, eubacteria and archaebacteria. The physiological relevance of queuine has yet to be determined. The enzyme responsible for the base-exchange reaction is called tRNA guanine transglycosylase (TGT). While the eubacterial and archael forms of TGT have been well characterized, very little is known about the eukaryotic enzyme.