Purification and characterization of cytochrome c-553 from Helicobacter pylori.
Helicobacter pylori, a microaerophilic Gram-negative spiral bacterium residing in the human stomach, contains a small size soluble cytochrome c. This cytochrome c was purified from the soluble fraction of H. pylori by conventional chromatographies involving octyl-cellulose and CM-Toyopearl. Its reduced form gave an alpha absorption band at 553 nm, and thus the cytochrome was named H. pylori cytochrome c-553. The cytochrome, giving a band below 10,000 Da upon SDS-PAGE, was determined to have a mass of 8,998 by time of flight mass spectroscopy. Its N-terminal peptide sequence was TDVKALAKS---, indicating that the nascent polypeptide was cleaved to produce a signal peptide of 19 amino acid residues and a mature protein composed of 77 amino acid residues. The cb-type cytochrome c oxidase oxidized ferrocytochrome c-553 of this bacterium actively (V(max) of about 250 s(-1)) with a small K(m) (0.9 microM). Analysis of the effect of the salt concentration on the oxidase activity indicated that oxidation of cytochrome c-553 is highly inhibited under high ionic conditions. The amino acid sequence of H. pylori cytochrome c-553 showed the closest similarity to that of Desulfovibrio vulgaris cytochrome c-553, and these sequences showed a weak relationship to that of the cytochrome c(8)-group among class I cytochromes c.
Koyanagi
S
S
Department of Biochemical System Engineering, Kyushu Institute of Technology, Kawazu Iizuka, Fukuoka 820-8502, Japan. sone@bse.kyutech.ac.jp
Nagata
K
K
Tamura
T
T
Tsukita
S
S
Sone
N
N
D000595:Amino Acid Sequence; D002852:Chromatography, Ion Exchange; D003574:Cytochrome c Group / Q000737:chemistry / Q000302:isolation & purification*; D004591:Electrophoresis, Polyacrylamide Gel; D016480:Helicobacter pylori / Q000201:enzymology*; D006863:Hydrogen-Ion Concentration; D013058:Mass Spectrometry; D008969:Molecular Sequence Data; D008970:Molecular Weight; D010084:Oxidation-Reduction; D011189:Potassium Chloride / Q000378:metabolism; D017386:Sequence Homology, Amino Acid
D003574:Cytochrome c Group; C083951:cytochrome c553; D011189:Potassium Chloride; C022302:cytochrome C-552