Characterization of two novel human small heat shock proteins: protein kinase-related HspB8 and testis-specific HspB9.

Using search profiles based on the conserved alpha-crystallin domain that is characteristic for small heat shock proteins (sHsps), we traced two new human sHsps. One of these, being the eighth known human sHsp and thus named HspB8, was recently described as a serine-threonine protein kinase (H11), but not identified as an sHsp (C.C.

Partially deglycosylated human choriogonadotropin, stabilized by intersubunit disulfide bonds, shows full bioactivity.

Several studies indicate that in human choriogonadotropin the N-linked oligosaccharide at position 52 of the alpha-subunit is important for bioactivity. We have generated choriogonadotropin mutants in which the alpha52 glycosylation site is removed and the alpha and beta subunits are covalently linked by intersubunit disulfide bonds. These mutants display wild-type receptor binding and bioactivity.

Structure-based design and protein engineering of intersubunit disulfide bonds in gonadotropins.

Pairs of cystine residues were introduced in the alpha- and beta-subunits of human choriogonadotropin at positions with optimal geometries for the formation of disulfide bonds. Using the homology with luteinizing hormone and follicle stimulating hormone, similar mutations were carried out in these glycoprotein hormones. In nearly all mutants the corresponding disulfide bonds were formed leading to a non-natural, covalent linkage between the alpha- and beta-subunits.

Evaluation of subunit truncation and the nature of the spacer for single chain human gonadotropins.

Three single chain gonadotropins were designed based on the three-dimensional-structure of human choriogonadotropin and structure/activity relationships of the glycoprotein hormones. In each single chain, the C-terminal end of the human choriogonadotropin beta subunit is connected via Ser-Gly repeats to the N-terminal end of the alpha subunit. In addition, two of the single chains have truncated subunits.

Recombinant rat luteinizing hormone; production by Chinese hamster ovary cells, purification and functional characterization.

Rat recombinant (rec) luteinizing hormone (LH) was produced in Chinese hamster ovary (CHO) cells, to enable studies on LH physiology in this species with homologous hormone. The synthesized hormone was purified, and characterized physico-chemically and biologically in comparison with highly purified preparations of rat pituitary (pit) LH (NIDDK-rLH-I-7 and I-9) and to highly purified urinary (NIH, CR-121) and rec forms of human chorionic gonadotropin (hCG). The 33 kD molecular mass of rat recLH, as determined by SDS-polyacrylamide gel electrophoresis (SDS-PAGE) and Western blot, was comparable with the 32 kD size of pitLH.