ウシラクトフェリンのタンパク質分解由来機能的モノフェリックCローブの1.9Å分解能結晶構造解析
The crystal structure of a proteolytically isolated C-lobe of bovine lactoferrin was determined at 1.9 Å resolution using molecular replacement with the C-terminal half of intact bovine lactoferrin as a search model, yielding an R-factor of 0.193. The refined model includes 2593 protein atoms (residues 342–676 and 681–685), 124 carbohydrate atoms from ten monosaccharide units across three glycan chains, one Fe³⁺ ion, one carbonate ion, two Zn²⁺ ions, and 230 water molecules. Ten disulfide bonds were identified; the Cys481–Cys675 pair forms an inter-domain link at 2.01 Å, and Cys405–Cys684 bridges the main C-lobe fragment to a hydrolyzed pentapeptide. Six inter-domain hydrogen bonds were observed, exceeding the four reported in intact lactoferrin, despite similar domain orientations. Two zinc ions located outside the iron-binding cleft contribute to crystal packing. The structure exhibits extensive intermolecular hydrogen bonding, ranking it among the most densely packed members of the transferrin superfamily.
An inter-domain disulfide bridge between Cys481 and Cys675 stabilizes the C-lobe fold, while two zinc ions located outside the iron-binding cleft contribute to crystal lattice stabilization through metal-mediated packing interactions.
The delivery route is not clearly identifiable from this paper. For hydrogen intake, inhalation is the most efficient route; inhalation, however, carries explosion risk (empirical LFL of 10%; high-concentration devices are not recommended).
See also:
https://h2-papers.org/en/papers/12888354