The Molecular Biology of Avian Gonadotropin1

Abstract

ABSTRACT Complimentary DNA for precursor molecules of chicken and quail luteinizing hormone (LH) /3 subunits have been cloned. From nucleotide sequences of the cDNA, the primary structures of the LH /3 subunit molecules of these avian species were deduced. The primary structures were similar, the amino acid sequence homology being 91.6%. For the a subunit, cloning of cDNA has been performed also in these two avian species. Predicted primary structures of the a subunit molecules of these birds were completely identical, although nucleotide sequences of their cDNA were slightly different. The LH /3 subunit molecules of both birds had 15 Pro residues at the same positions. Ten of them shared the same positions with Pro residues in the mammalian LH /3 subunits, in which about 20 Pro residues exist. Prediction of the secondary structure and exposure of each amino acid residue in the chicken LH 0 subunit molecule were performed with the aid of a computer program for protein engineering. It was revealed that most of 15 Pro residues did not exist in regions where the $ structure was predicted but were distributed in regions where a turn or loop was predicted. In addition, three of four Tyr residues were predicted to be located inside the molecule. These results suggest that the predicted presence of a number of Pro residues in the loop of the secondary structure is a cause of high animal group and hormone specificities in the LH-LH receptor interaction. The predicted internal localization of Tyr residues is considered to cause loss of receptor binding activity by conventional radioiodi-nation procedures. (Key words: luteinizing hormone, follicle-stimulating hormone, primary struc-ture, secondary structure, reproduction

Similar works

Full text

thumbnail-image
oai:CiteSeerX.psu:10.1.1.922.3568Last time updated on 11/1/2017

This paper was published in CiteSeerX.

Having an issue?

Is data on this page outdated, violates copyrights or anything else? Report the problem now and we will take corresponding actions after reviewing your request.