Ray F R, Barden J A, Kemp B E
University of Sydney, Department of Anatomy, Australia.
Eur J Biochem. 1993 Jan 15;211(1-2):205-11. doi: 10.1111/j.1432-1033.1993.tb19887.x.
The structure of the biologically active N-terminal domain of human parathyroid-hormone-related protein (residues 1-34) containing an Ala substituted for a His in position 26 was studied by two-dimensional proton NMR spectroscopy. Unambiguous NMR assignments of all backbone and side-chain hydrogens were made with the aid of totally correlated spectroscopy experiments, which provided through-bond 1H-1H connectivities, and NOE spectroscopy, which provided through-space and sequential backbone connectivities. The NMR data were utilized in distance-geometry algorithms to generate a family of structures. The major structural features include two segments of alpha-helix extending from Glu4 to Lys13 and from Leu27 to Thr33, with two turns from Gln16 to Arg19 and Phe22 to His25. A salt-bridge appears likely between Arg20 and Glu30 which may be critical for holding the receptor-binding domain together.
