HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Hettmann, T. Articles by Schäfer, G. Search for Related Content PubMed PubMed Citation Articles by Hettmann, T. Articles by Schäfer, G. Social Bookmarking                      What's this?

J Biol Chem, Vol. 273, Issue 20, 12032-12040, May 15, 1998

Cytochrome b_558/566 from the Archaeon Sulfolobus acidocaldarius
A NOVEL HIGHLY GLYCOSYLATED, MEMBRANE-BOUND B-TYPE HEMOPROTEIN

Thomas Hettmann, Christian L. Schmidt, Stefan Anemüller, Ulrich Zähringer^§, Hermann Moll^§, Arnd Petersen^§, and Günter Schäfer

From the  Institut für Biochemie, Medizinische Universität zu Lübeck, Ratzeburger Allee 160, 23538 Lübeck, Germany and the ^§ Forschungszentrum Borstel, Zentrum für Medizin und Biowissenschaften, Parkallee 1-40, 23845 Borstel, Germany

In this study we re-examined the inducible cytochrome b_558/566 from the archaeon Sulfolobus acidocaldarius (DSM 639), formerly thought to be a component of a terminal oxidase (Becker, M., and Schäfer, G. (1991) FEBS Lett. 291, 331-335). An improved purification method increased the yield of the protein and allowed more detailed investigations. Its molecular mass and heme content have been found to be 64,210 Da and 1 mol of heme/mol of protein, respectively. It is only detectable in cells grown at low oxygen tensions. The composition of the growth medium also exerts significant influence on the cytochrome b_558/566 content of S. acidocaldarius membranes. The cytochrome exhibits an extremely high redox potential of +400 mV and shows no CO reactivity; a ligation other than a His/His-coordination of axial ligands appears likely. It turned out to be highly glycosylated (more than 20% of its molecular mass are sugar residues) and is probably exposed to the outer surface of the plasma membrane. The sugar moiety consists of several O-glycosidically linked mannoses and at least one N-glycosidically linked hexasaccharide comprising two glucoses, two mannoses, and two N-acetyl-glucosamines. The gene of the cytochrome (cbsA) has been sequenced, revealing an interesting predicted secondary structure with two putative -helical membrane anchors flanking the majority of a mainly -pleated sheet structure containing unusually high amounts of serine and threonine. A second gene (cbsB) was found to be cotranscribed. The latter displays extreme hydrophobicity and is thought to form a functional unit with cytochrome b_558/566 in vivo, although it did not copurify with the latter. Sequence comparisons show no similarity to any entry in data banks indicating that this cytochrome is indeed a novel kind of b-type hemoprotein. A cytochrome c analogous function in the pseudoperiplasmic space of S. acidocaldarius is discussed.

CiteULike

Complore

Connotea

Del.icio.us

Digg

Reddit

Technorati

This article has been cited by other articles:

				E. T. Larson, D. Reiter, M. Young, and C. M. Lawrence Structure of A197 from Sulfolobus Turreted Icosahedral Virus: a Crenarchaeal Viral Glycosyltransferase Exhibiting the GT-A Fold. J. Virol., August 1, 2006; 80(15): 7636 - 7644. [Abstract] [Full Text] [PDF]

				J. Eichler and M. W. W. Adams Posttranslational Protein Modification in Archaea Microbiol. Mol. Biol. Rev., September 1, 2005; 69(3): 393 - 425. [Abstract] [Full Text] [PDF]

				U. Kappler, L. I. Sly, and A. G. McEwan Respiratory gene clusters of Metallosphaera sedula - differential expression and transcriptional organization Microbiology, January 1, 2005; 151(1): 35 - 43. [Abstract] [Full Text] [PDF]

				C. Vieille and G. J. Zeikus Hyperthermophilic Enzymes: Sources, Uses, and Molecular Mechanisms for Thermostability Microbiol. Mol. Biol. Rev., March 1, 2001; 65(1): 1 - 43. [Abstract] [Full Text] [PDF]

				G. Schafer, M. Engelhard, and V. Muller Bioenergetics of the Archaea Microbiol. Mol. Biol. Rev., September 1, 1999; 63(3): 570 - 620. [Abstract] [Full Text] [PDF]