# Crystal structure of a proteolytically generated functional monoferric C-lobe of bovine lactoferrin at 1.9A resolution.
> 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


## Abstract

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.

### Mechanism

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.

## Bibliographic

- **Authors**: Sharma S, Jasti J, Kumar J, Mohanty AK, Singh TP
- **Journal**: J Mol Biol
- **Year**: 2003 (2003-08-08)
- **PMID**: [12888354](https://pubmed.ncbi.nlm.nih.gov/12888354/)
- **DOI**: [10.1016/s0022-2836(03)00717-4](https://doi.org/10.1016/s0022-2836(03)00717-4)
- **Study type**: other
- **Delivery route**: not specified
- **Effect reported**: not assessed

## Delivery context

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).

## Safety notes

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:
- [Inhalation concentration and LFL / UFL](https://h2-papers.org/en/safety-notes/inhalation-concentration)
- [Consumer Affairs Agency accident cases](https://h2-papers.org/en/safety-notes/accident-cases)

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> **Cite as**: H2 Papers — PMID 12888354. https://h2-papers.org/en/papers/12888354
> **Source**: PubMed PMID [12888354](https://pubmed.ncbi.nlm.nih.gov/12888354/)