Conformational flexibility in crystal structures of human 11beta-hydroxysteroid dehydrogenase type I provide insights into glucocorticoid interconversion and enzyme regulation.
Human 11beta-hydroxysteroid dehydrogenase type I (11beta-HSD1) is an ER-localized membrane protein that catalyzes the interconversion of cortisone and cortisol. In adipose tissue, excessive cortisol production through 11beta-HSD1 activity has been implicated in the pathogenesis of type II diabetes and obesity. We report here biophysical, kinetic, mutagenesis, and structural data on two ternary complexes of 11beta-HSD1. The combined results reveal flexible active site interactions relevant to glucocorticoid recognition and demonstrate how four 11beta-HSD1 C termini converge to form an as yet uncharacterized tetramerization motif. A C-terminal Pro-Cys motif is localized at the center of the tetramer and forms reversible enzyme disulfides that alter enzyme activity. Conformational flexibility at the tetramerization interface is coupled to structural changes at the enzyme active site suggesting how the central Pro-Cys motif may regulate enzyme activity. Together, the crystallographic and biophysical data provide a structural framework for understanding 11beta-HSD1 activities and will ultimately facilitate the development of specific inhibitors.
Hosfield
David J
DJ
Syrrx Inc., San Diego, California 92121, USA. david.hosfield@syrrx.com
Wu
Yiqin
Y
Skene
Robert J
RJ
Hilgers
Mark
M
Jennings
Andy
A
Snell
Gyorgy P
GP
Aertgeerts
Kathleen
K
D042842:11-beta-Hydroxysteroid Dehydrogenases / Q000737:chemistry*; D020816:Amino Acid Motifs; D001665:Binding Sites; D003001:Cloning, Molecular; D003348:Cortisone / Q000737:chemistry; D018360:Crystallography, X-Ray; D003545:Cysteine / Q000737:chemistry; D003924:Diabetes Mellitus, Type 2 / Q000378:metabolism; D019281:Dimerization; D004220:Disulfides / Q000737:chemistry; D004721:Endoplasmic Reticulum / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004926:Escherichia coli / Q000378:metabolism; D005938:Glucocorticoids / Q000737:chemistry*; D006801:Humans; D006854:Hydrocortisone / Q000737:chemistry; D007700:Kinetics; D013058:Mass Spectrometry; D008958:Models, Molecular; D016296:Mutagenesis; D009765:Obesity / Q000378:metabolism; D010100:Oxygen / Q000378:metabolism; D017354:Point Mutation; D011392:Proline / Q000737:chemistry; D011485:Protein Binding; D011487:Protein Conformation; D017434:Protein Structure, Tertiary; D011994:Recombinant Proteins / Q000737:chemistry
D004220:Disulfides; D004791:Enzyme Inhibitors; D005938:Glucocorticoids; D011994:Recombinant Proteins; D011392:Proline; D042842:11-beta-Hydroxysteroid Dehydrogenases; D003545:Cysteine; D010100:Oxygen; D003348:Cortisone; D006854:Hydrocortisone