46 research outputs found
12-Oxophytodienoate-10,11-Reductase: Occurrence of Two Isoenzymes of Different Specificity against Stereoisomers of 12-Oxophytodienoic Acid
Identification and Characterization of an 18-Kilodalton, VAMP-Like Protein in Suspension-Cultured Carrot Cells
Analysis of the Aspergillus fumigatus Proteome Reveals Metabolic Changes and the Activation of the Pseurotin A Biosynthesis Gene Cluster in Response to Hypoxia
The mold Aspergillus fumigatus is the most important airborne fungal pathogen. Adaptation to hypoxia represents an important virulence attribute for A. fumigatus. Therefore, we aimed at obtaining a comprehensive overview about this process on the proteome level. To ensure highly reproducible growth conditions, an oxygen-controlled, glucose-limited chemostat cultivation was established. Two-dimensional gel electrophoresis analysis of mycelial and mitochondrial proteins as well as two-dimensional Blue Native/SDS-gel separation of mitochondrial membrane proteins led to the identification of 117 proteins with an altered abundance under hypoxic in comparison to normoxic conditions. Hypoxia induced an increased activity of glycolysis, the TCA-cycle, respiration, and amino acid metabolism. Consistently, the cellular contents in heme, iron, copper, and zinc increased. Furthermore, hypoxia induced biosynthesis of the secondary metabolite pseurotin A as demonstrated at proteomic, transcriptional, and metabolite levels. The observed and so far not reported stimulation of the biosynthesis of a secondary metabolite by oxygen depletion may also affect the survival of A. fumigatus in hypoxic niches of the human host. Among the proteins so far not implicated in hypoxia adaptation, an NO-detoxifying flavohemoprotein was one of the most highly up-regulated proteins which indicates a link between hypoxia and the generation of nitrosative stress in A. fumigatus
Cabbage Cryoprotectin Is a Member of the Nonspecific Plant Lipid Transfer Protein Gene Family
Cloning and Characterization of a Coronatine-Regulated Tyrosine Aminotransferase from Arabidopsis
Multiple Functions for the C Terminus of the PsaD Subunit in the Cyanobacterial Photosystem I Complex
Identification of Novel Mitochondrial Protein Components of Chlamydomonas reinhardtii. A Proteomic Approach
Pure mitochondria of the photosynthetic alga Chlamydomonas reinhardtii were analyzed using blue native-polyacrylamide gel electrophoresis (BN-PAGE). The major oxidative phosphorylation complexes were resolved: F(1)F(0)-ATP synthase, NADH-ubiquinone oxidoreductase, ubiquinol-cytochrome c reductase, and cytochrome c oxidase. The oligomeric states of these complexes were determined. The F(1)F(0)-ATP synthase runs exclusively as a dimer, in contrast to the C. reinhardtii chloroplast enzyme, which is present as a monomer and subcomplexes. The sequence of a 60-kD protein, associated with the mitochondrial ATP synthase and with no known counterpart in any other organism, is reported. This protein may be related to the strong dimeric character of the algal F(1)F(0)-ATP synthase. The oxidative phosphorylation complexes resolved by BN-PAGE were separated into their subunits by second dimension sodium dodecyl sulfate-PAGE. A number of polypeptides were identified mainly on the basis of their N-terminal sequence. Core I and II subunits of complex III were characterized, and their proteolytic activities were predicted. Also, the heterodimeric nature of COXIIA and COXIIB subunits in cytochrome c oxidase was demonstrated. Other mitochondrial proteins like the chaperone HSP60, the alternative oxidase, the aconitase, and the ADP/ATP carrier were identified. BN-PAGE was also used to approach the analysis of the major chloroplast protein complexes of C. reinhardtii
Mapping of the interactions between partition proteins Delta and Omega of plasmid pSM19035 from Streptococcus pyogenes
Formation of the segrosome, a nucleoprotein complex crucial for proper functioning of plasmid
partition systems, involves interactions between specific partition proteins (ParA-like and ParBlike),
ATP and specific DNA sequences (the centromeric sites). Although partition systems have
been studied for many years, details of the segrosome formation are not yet clear. Organization of
the pSM19035-encoded partition system is unique; in contrast with other known par systems,
here, the d and v genes do not constitute an operon. Moreover, Omega [a ParB-like protein which
has a Ribbon-Helix-Helix (RHH) structure] recognizes multiple centromeric sequences located in
the promoters of d, v and copS (copy-number control gene). The ParA-like protein Delta is a
Walker-type ATPase. In this work, we identify the interaction domains and requirements for
dimerization and hetero-interactions of the Delta and Omega proteins of pSM19035 plasmid. The
RHH structures are involved in Omega dimerization in vivo and its N-terminal unstructured part is
indispensable for association with Delta, both in vivo and in vitro. Omega does not need to form
dimers to interact with Delta. ATP binding is not required for Delta dimerization but is important for
interaction with Omega in vivo. The in vitro interaction between Delta and Omega depends on
ATP but does not require the presence of specific DNA segments (the centromere) recognized by
Omega. The C-terminal part of the Delta protein (aa 198–284) is indispensable for interaction
with Omega. Delta most probably interacts with Omega as a dimer since two amino acid
substitutions in a conserved region between the A9 and B motifs abolish both the dimerization of
Delta and its interaction with Omega