Purification and characterization of eukaryotic ATP-dependent transporters homologously expressed in Pichia pastoris for structural studies by cryo-electron microscopy.

Membrane proteins play an essential role in all living organisms. Although there have been numerous efforts in the past to elucidate the structure and function of eukaryotic primary active transporters, knowledge about the majority of these membrane proteins is still minimal. This is often due to their low availability and complex handling.

Structural and functional investigation of ABC transporter STE6-2p from reveals unexpected interaction with sterol molecules.

Adenosine triphosphate (ATP)-binding cassette (ABC) transporters are multidomain transmembrane proteins, which facilitate the transport of various substances across cell membranes using energy derived from ATP hydrolysis. They are important drug targets since they mediate decreased drug susceptibility during pharmacological treatments. For the methylotrophic yeast , a model organism that is a widely used host for protein expression, the role and function of its ABC transporters is unexplored.

Production of Membrane Proteins in Pseudomonas stutzeri.

Functional and structural studies on membrane proteins are often hampered by insufficient yields, misfolding and aggregation during the production and purification process. Escherichia coli is the most commonly used expression host for the production of recombinant prokaryotic integral membrane proteins. However, in many cases expression hosts other than E.

Mechanistic and structural diversity between cytochrome isoforms of .

The treatment of infectious diseases caused by multidrug-resistant pathogens is a major clinical challenge of the 21st century. The membrane-embedded respiratory cytochrome -type oxygen reductase is a critical survival factor utilized by pathogenic bacteria during infection, proliferation and the transition from acute to chronic states. encodes for two cytochrome isoforms that are both involved in respiration under oxygen limited conditions.

Subunit CcoQ is involved in the assembly of the Cbb-type cytochrome c oxidases from Pseudomonas stutzeri ZoBell but not required for their activity.

The Cbb-type cytochrome c oxidases (Cbb-CcOs), the second most abundant CcOs, catalyze the reduction of molecular oxygen to water, even at micromolar oxygen concentrations. In Pseudomonas stutzeri ZoBell, two tandemly organized cbb-operons encode the isoforms Cbb-1 and Cbb-2 both possessing subunits CcoN, CcoO and CcoP. However, only the cbb-2 operon contains an additional ccoQ gene.

Identification and Characterization of the Novel Subunit CcoM in the cbb3₃Cytochrome c Oxidase from Pseudomonas stutzeri ZoBell.

Unlabelled: Cytochrome c oxidases (CcOs), members of the heme-copper containing oxidase (HCO) superfamily, are the terminal enzymes of aerobic respiratory chains. The cbb3-type cytochrome c oxidases (cbb3-CcO) form the C-family and have only the central catalytic subunit in common with the A- and B-family HCOs. In Pseudomonas stutzeri, two cbb3 operons are organized in a tandem repeat.

A decade of crystallization drops: crystallization of the cbb3 cytochrome c oxidase from Pseudomonas stutzeri.

The cbb3 cytochrome c oxidases are distant members of the superfamily of heme copper oxidases. These terminal oxidases couple O2 reduction with proton transport across the plasma membrane and, as a part of the respiratory chain, contribute to the generation of an electrochemical proton gradient. Compared with other structurally characterized members of the heme copper oxidases, the recently determined cbb3 oxidase structure at 3.

Biochemical and biophysical characterization of the two isoforms of cbb3-type cytochrome c oxidase from Pseudomonas stutzeri.

The cbb3-type cytochrome c oxidases (cbb3-CcOs) are members of the heme-copper oxidase superfamily that couple the reduction of oxygen to translocation of protons across the membrane. The cbb3-CcOs are present only in bacteria and play a primary role in microaerobic respiration, being essential for nitrogen-fixing endosymbionts and for some human pathogens. As frequently observed in Pseudomonads, Pseudomonas stutzeri contains two independent ccoNO(Q)P operons encoding the two cbb3 isoforms, Cbb3-1 and Cbb3-2.

The structure of cbb3 cytochrome oxidase provides insights into proton pumping.

The heme-copper oxidases (HCOs) accomplish the key event of aerobic respiration; they couple O2 reduction and transmembrane proton pumping. To gain new insights into the still enigmatic process, we structurally characterized a C-family HCO--essential for the pathogenicity of many bacteria--that differs from the two other HCO families, A and B, that have been structurally analyzed. The x-ray structure of the C-family cbb3 oxidase from Pseudomonas stutzeri at 3.