Purification of a ccb -type quinol oxidase specifically induced in a deep-sea barophilic bacterium, Shewanella sp. strain DB-172F

Abstract

We investigated for the first time the respiratory chain system of a deep-sea barophilic bacterium, Shewanella sp. strain DB-172F. A membrane-bound ccb-type quinol oxidase, from cells grown at 60 MPa pressure, was purified to an electrophoretically homogeneous state. The purified enzyme complex consisted of four kinds of subunits with molecular masses of 98, 66, 18.5, and 15kDa, and it contained 0.96 mol of protoheme and 1.95mol of covalently bound heme c per mol of enzyme. Only protoheme in the enzyme reacted with CO and CN-, and the catalytic activity of the enzyme was 50% inhibited by 4 microM CN-. The isoelectric point of the native enzyme complex was determined to be 5.0. This enzyme was specifically induced only under conditions of elevated hydrostatic pressure, and high levels were expressed in cells grown at 60 MPa. The membranes isolated from cells grown at atmospheric pressure (0.1 MPa) exhibited high levels of both cytochrome c oxidase and N,N,N',N'-tetramethyl-p-phenylenediamine (TMPDH2)-oxidase activity. These results suggest the presence of two kinds of respiratory chains regulated in response to pressure in the deep-sea bacterium DB-172F.

The Respiratory System of the PiezophilePhotobacterium profundumSS9 Grown under Various Pressures

“…Many y To whom correspondence should be addressed. Fax: +81-3-5317-9433; E-mail: htamegai@chs.nihon-u.ac.jp studies have been carried out on the respiratory system of S. violacea and on related strains for comparison, [19][20][21][22] but it remains unknown whether this phenomenon observed in S. violacea is universal to piezophiles.…”

Pressure Regulation of Soluble Cytochromes c in a Deep-Sea Piezophilic Bacterium, Shewanella violacea

“…These findings suggested that the expression of the respiratory system may be regulated by hydrostatic pressure, and this regulation may play some role in adaptation to high hydrostatic pressure. Indeed, expression of cytochromes is regulated by pressure in S. benthica DB172F (27,28) and S. violacea DSS12 (29).…”

Bioprocess engineering approaches for the production of marine enzymes

“…strain DB-172F was investigated by Qureshi et al, 1998. A membrane-bound ccb-type quinol oxidase was obtained from cells grown in a pressurized vessel.…”