title: Effect of N-terminal residues on the structural stability of recombinant horse L-chain apoferritin in an acidic environment.
abstract: The denaturation of recombinant horse L-chain apoferritin (rLF), which is composed of 24 L-chain subunits, in acidic solution was studied. Using two rLF mutants, lacking four (Fer4) or eight (Fer8) N-terminal amino acid residues, the effect of N-terminal residues on the protein's stability was investigated. Of the two mutants and wild-type rLF, the tertiary and secondary structures of Fer8 were found to be most sensitive to an acidic environment. The Fer8 protein dissociated easily into subunit dimers at or below pH 2.0. Comparing the crystal structures of the mutant proteins, deletion of the N-terminal residues was found to result in fewer inter- and intra-subunit hydrogen bonds. The loss of these bonds is assumed to be responsible for lower endurance against acidic denaturation in N-terminus-deleted mutants. These results indicated that the inter- and intra-subunit hydrogen bonds of N-terminal residues affect the denaturation, especially oligomer formation of apoferritin subunits and will be of use in designing ferritin-based nanodevices.
authors.affiliation: CREST, Japan Science and Technology Agency, 4-1-8 Honcho, Kawaguchi, Saitama, 332-0012, Japan.
authors.forename: Keiko
authors.initials: K
authors.lastname: Yoshizawa
authors.forename: Yumiko
authors.initials: Y
authors.lastname: Mishima
authors.forename: Sam-Yong
authors.initials: SY
authors.lastname: Park
authors.forename: Jonathan G
authors.initials: JG
authors.lastname: Heddle
authors.forename: Jeremy R H
authors.initials: JR
authors.lastname: Tame
authors.forename: Kenji
authors.initials: K
authors.lastname: Iwahori
authors.forename: Mime
authors.initials: M
authors.lastname: Kobayashi
authors.forename: Ichiro
authors.initials: I
authors.lastname: Yamashita
mesh_terms: D000818:Animals; D001052:Apoferritins / Q000737:chemistry* / Q000235:genetics; D002942:Circular Dichroism; D018360:Crystallography, X-Ray; D019281:Dimerization; D006736:Horses / Q000235:genetics; D006860:Hydrogen Bonding; D006863:Hydrogen-Ion Concentration; D008958:Models, Molecular; D011489:Protein Denaturation; D021122:Protein Subunits / Q000737:chemistry; D011994:Recombinant Proteins / Q000737:chemistry
chemical_list: D021122:Protein Subunits; D011994:Recombinant Proteins; D001052:Apoferritins