Isolation of a ferritin from Bacteroides fragilis.
A ferritin was isolated from the obligate anaerobe Bacteroides fragilis. Estimated molecular masses were 400 kDa for the holomer and 16.7 kDa for the subunits. A 30-residue N-terminal amino acid sequence was determined and found to resemble the sequences of other ferritins (human H-chain ferritin, 43% identity; Escherichia coli gen-165 product, 37% identity) and to a lesser degree, bacterioferritins (E. coli bacterioferritin, 20% identity). The protein stained positively for iron, and incorporated 59Fe when B. fragilis was grown in the presence of [59Fe]citrate. However, the isolated protein contained only about three iron atoms per molecule, and contained no detectable haem. This represents the first isolation of a ferritin protein from bacteria. It may alleviate iron toxicity in the presence of oxygen.
Rocha
E R
ER
University Department of Bacteriology and Immunology, Western Infirmary, Glasgow, UK.
Andrews
S C
SC
Keen
J N
JN
Brock
J H
JH
D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry / Q000302:isolation & purification*; D001441:Bacteroides fragilis / Q000737:chemistry*; D005293:Ferritins / Q000737:chemistry / Q000302:isolation & purification*; D008969:Molecular Sequence Data; D012689:Sequence Homology, Nucleic Acid
D001426:Bacterial Proteins; D005293:Ferritins