Structure of recombinant human lactoferrin expressed in Aspergillus awamori

Abstract

Human lactoferrin (hLf) has considerable potential as a therapeutic agent. Overexpression of hLf in the fungus Aspergillus awamori has resulted in the availability of very large quantities of this protein. Here, the three-dimensional structure of the recombinant hLf has been determined by X-ray crystallography at a resolution of 2.2 A Ê . The ®nal model, comprising 5339 protein atoms (residues 1±691, 294 solvent molecules, two Fe 3+ and two CO 2À 3 ions), gives an R factor of 0.181 (free R = 0.274) after re®nement against 32 231 re¯ections in the resolution range 10±2.2 A Ê . Superposition of the recombinant hLf structure onto the native milk hLf structure shows a very high level of correspondence; the mainchain atoms for the entire polypeptide can be superimposed with an r.m.s. deviation of only 0.3 A Ê and there are no signi®cant differences in side-chain conformations or in the iron-binding sites. Dynamic properties, as measured by B-value distributions or iron-release kinetics, also agree closely. This shows that the structure of the protein is not affected by the mode of expression, the use of strainimprovement procedures or the changes in glycosylation due to the fungal system.

Helicobacter pyloriPersistence: an Overview of Interactions betweenH. pyloriand Host Immune Defenses

“…The gastric epithelial layer constitutes a physical barrier that prevents entry of bacteria into the gastric mucosa. Ribbon diagrams of lactoferrin, ␤-defensins, and LL-37 are derived from published structures (24,200,218).…”

An Investigation of the Protonation States of Human Lactoferrin Iron-Binding Protein

“…These structures had the Protein Data Bank codes of 1LFH [20] determined at 2.80 Å resolution and 1B0L [5] determined at 2.20 Å resolution, respectively. All water molecules present in both PDB structure fi les were removed, according to the protocol for conducting computational experiments using H++ server [13].…”

“…Ferric ion is stabilized in the protein binding site through two oxygens from carbonate ion. X-ray high-resolution structures of lactoferrins [5][6][7][8][9] isolated from various species show a high degree of similarity, approximately 70% identity between their structures. And each of the family members has a high degree of internal similarity ~ 40% of sequence identity between N-lobe and C-lobe [10,11].…”

“…The X-ray crystallographic structure of this glycoprotein, 1B0L Protein Data Bank (PDB) code [5], consists of a polypeptide chain of 691 amino acid residues. Its structure is folded in two globular lobes referred as N-(residues 1-333) and C-(residues 345-691) lobes connected with a short helical peptide chain (residue 334-344).…”

Lactoferrin: Analysis of the Structure Profile

“…The process of iron binding and release from lactoferrin molecule depends on its molecular properties and on the location where it is expressed. To help gain more insights into the process of iron uptake, it is important to investigate the structure similarities of lactoferrin molecules isolated from different species (see Table 2) and outline the structure differences and similarities between lactoferrin [7] and serum transferrin [12]. …”