Catalogo Articoli (Spogli Riviste)

OPAC HELP

Titolo:
Abortive assembly of succinate-ubiquinone reductase (complex II) in a ferrochelatase-deficient mutant of Escherichia coli
Autore:
Nihei, C; Nakayashiki, T; Nakamura, K; Inokuchi, H; Gennis, RB; Kojima, S; Kita, K;
Indirizzi:
Univ Tokyo, Grad Sch Med, Dept Biomed Chem, Bunkyo Ku, Tokyo 1130033, Japan Univ Tokyo Tokyo Japan 1130033 med Chem, Bunkyo Ku, Tokyo 1130033, Japan Kyoto Univ, Grad Sch Sci, Dept Biol Sci, Sakyo Ku, Kyoto 6068224, Japan Kyoto Univ Kyoto Japan 6068224 Biol Sci, Sakyo Ku, Kyoto 6068224, Japan Univ Tokyo, Inst Med Sci, Dept Parasitol, Minato Ku, Tokyo 1080071, Japan Univ Tokyo Tokyo Japan 1080071 arasitol, Minato Ku, Tokyo 1080071, Japan Univ Illinois, Dept Biochem, Urbana, IL 61801 USA Univ Illinois Urbana ILUSA 61801 ois, Dept Biochem, Urbana, IL 61801 USA
Titolo Testata:
MOLECULAR GENETICS AND GENOMICS
fascicolo: 3, volume: 265, anno: 2001,
pagine: 394 - 404
SICI:
1617-4615(200105)265:3<394:AAOSR(>2.0.ZU;2-N
Fonte:
ISI
Lingua:
ENG
Soggetto:
LIGHT-SENSITIVE MUTANTS; FUMARATE REDUCTASE; CYTOCHROME-C; BACILLUS-SUBTILIS; RESPIRATORY-CHAIN; PROTOPORPHYRIN-IX; AXIAL LIGANDS; HEME; OXIDOREDUCTASE; DEHYDROGENASE;
Keywords:
enzyme assembly; succinate dehydrogenase; cytochrome b; hemH mutant; ferrochelatase;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
58
Recensione:
Indirizzi per estratti:
Indirizzo: Kita, K Univ Tokyo, Grad Sch Med, Dept Biomed Chem, Bunkyo Ku, 7-3-1 Hongo, Tokyo 1130033, Japan Univ Tokyo 7-3-1 Hongo Tokyo Japan 1130033 , Tokyo 1130033, Japan
Citazione:
C. Nihei et al., "Abortive assembly of succinate-ubiquinone reductase (complex II) in a ferrochelatase-deficient mutant of Escherichia coli", MOL GENET G, 265(3), 2001, pp. 394-404

Abstract

Heme molecules play important roles in electron transfer by redox proteinssuch as cytochromes. In addition, a structural role for heme in protein folding and the assembly of enzymes has been suggested. Previous results obtained using Escherichia coli hemA mutants, which are unable to synthesize 5-aminolevulinic acid, a precursor of porphyrins and hemes, have demonstrateda requirement for heme biosynthesis in the assembly of a functional succinate-ubiquinone reductase (SQR or complex II), which is a component of the aerobic respiratory chain. In the present study, in order to investigate therole of the heme in the assembly of E. coli SQR, we used a hemH (encodes ferrochelatase) mutant that lacks the ability to insert iron into the porphyrin ring. The hemH mutant failed to insert functional SQR into the cytoplasmic membrane, and the catalytic portion of SQR [the flavoprotein subunit (Fp) and the iron-sulfur protein subunit (Ip)] was localized in the cytoplasmof the cell. It is of interest to note that protoporphyrin IX accumulated in the mutant cells and inactivated the cytoplasmic succinate dehydrogenase(SDH) activity associated with the catalytic Fp-Ip complex. In contrast, SQR was assembled into the membrane of a home-permeable hemH double mutant when hemin was present in the culture. Only a low level of SQR activity was found in the membrane when hemin was replaced by non-iron metalloporphyrins: Mn-, Co-, Ni-, Zn- and Cu-protoporphyrin IX, or protoporphyrin IX These results indicate that heme iron is indispensable for the functional assemblyof SQR in the cytoplasmic membrane of E. coli, and provide a new insight into the biological role of hence in the molecular assembly of the multi-subunit enzyme complex.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 06/04/20 alle ore 21:53:18