2 research outputs found
Different Growth Responses to Recombinant Human Growth Hormone in Three Siblings with Isolated Growth Hormone Deficiency Type IA due to 6.7Kb Deletion of GH1 Gene
Domain Structure and Denaturation of a Dimeric Mip-like Peptidyl-Prolyl <i>cis–trans</i> Isomerase from <i>Escherichia coli</i>
FKBP22, a protein expressed by <i>Escherichia coli</i>, possesses PPIase (peptidyl-prolyl <i>cis</i>-<i>trans</i> isomerase) activity, binds FK506 (an immunosuppressive
drug), and shares homology with <i>Legionella</i> Mip (a
virulence factor) and its related proteins. To understand the domain
structure and the folding–unfolding mechanism of Mip-like proteins,
we investigated a recombinant <i>E. coli</i> FKBP22 (His-FKBP22)
as a model protein. Limited proteolysis indicated that His-FKBP22
harbors an N-terminal domain (NTD), a C-terminal domain (CTD), and
a long flexible region linking the two domains. His-FKBP22, NTD<sup>+</sup> (NTD with the entire flexible region), and CTD<sup>+</sup> (CTD with a truncated flexible region) were unfolded by a two-state
mechanism in the presence of urea. Urea induced the swelling of dimeric
His-FKBP22 molecules at the pretransition state but dissociated it
at the early transition state. In contrast, guanidine hydrochloride
(GdnCl)-induced equilibrium unfolding of His-FKBP22 or NTD<sup>+</sup> and CTD<sup>+</sup> seemed to follow three-step and two-step mechanisms,
respectively. Interestingly, the intermediate formed during the unfolding
of His-FKBP22 with GdnCl was not a molten globule but was thought
to be composed of the partially unfolded dimeric as well as various
multimeric His-FKBP22 molecules. Dimeric His-FKBP22 did not dissociate
gradually with increasing concentrations of GdnCl. Very low GdnCl
concentrations also had little effect on the molecular dimensions
of His-FKBP22. Unfolding with either denaturant was found to be reversible,
as refolding of the unfolded His-FKBP22 completely, or nearly completely,
restored the structure and function of the protein. Additionally,
denaturation of His-FKBP22 appeared to begin at the CTD<sup>+</sup>