Pyruvate: ferredoxin oxidoreductase (POR; EC 18.104.22.168) catalyzes the thia-mine pyrophosphate-dependent oxidative decarboxylation of pyruvate to
form acetyl-CoA and CO2
. The thermophilic, obligate chemolithoauto-trophic hydrogen-oxidizing bacterium, Hydrogenobacter thermophilusTK-6,
via the reductive tricarboxylic acid cycle.
Aminotransferases catalyse synthetic and degradative reactions of amino
acids, and serve as a key linkage between central carbon and nitrogen
metabolism in most organisms. In this study, three aminotransferases (AT1,
AT2 and AT3) were purified and characterized fromHydrogenobacter
thermophilus, a hydrogen-oxidizing chemolithoautotrophic bacterium, which
has been reported to possess unique features in its carbon and nitrogen
The cell cycle-dependent element (CDE) and the cell cycle genes homology
region (CHR) control the transcription of genes with maximum expression
phase and in mitosis. Promoters of these genes are repressed by pro-teins binding to CDE⁄CHR elements in G0 and G1 phases. Relief from
repression begins in S phase and continues into G2
phase and mitosis.
The structural basis for the homotropic inhibition of pantothenate synthe-tase by the substrate pantoate was investigated by X-ray crystallography
and high-resolution NMR spectroscopic methods. The tertiary structure of
the dimeric N-terminal domain of Escherichia colipantothenate synthetase,
determined by X-ray crystallography to a resolution of 1.7 A˚
, showed a
second molecule of pantoate bound in the ATP-binding pocket.
Of the 600+ known proteases identified to date in mammals, a significant
percentage is involved or implicated in pathogenic and cancer processes.
The dipeptidyl peptidase IV (DPIV) gene family, comprising four enzyme
members [DPIV (EC 22.214.171.124), fibroblast activation protein, DP8 and DP9]
and two nonenzyme members [DP6 (DPL1) and DP10 (DPL2)], are inter-esting in this regard because of their multiple diverse functions,
The bacterial twin-arginine translocation (Tat) system is a protein targeting
pathway dedicated to the transport of folded proteins across the cytoplas-mic membrane. Proteins transported on the Tat pathway are synthesised as
precursors with N-terminal signal peptides containing a conserved amino
During embryogenesis, most of the mammalian skeletal system is preformed
as cartilaginous structures that ossify later. The different stages of cartilage
and skeletal development are well described, and several molecular factors
are known to influence the events of this enchondral ossification, especially
Although heat shock protein 70 (Hsp70) has been shown to markedly inhi-bit H2O2-induced apoptosis in C2C12 cells, and nucleolin⁄C23 has also
been implicated in apoptosis, the relationship of these two molecules is still
largely unknown. The aim of the current study was to investigate the
potential involvement of nucleolin⁄C23 in the antiapoptotic mechanism of
The translocation domain (T domain) of diphtheria toxin adopts a partially
folded state, the so-called molten globule state, to become functional at
acidic pH. We compared, using hydrogen⁄deuterium exchange experiments
associated with MS, the structures of the T domain in its soluble folded
state at neutral pH and in its functional molten globule state at acidic pH.
The class of nonribosomally assembled siderophores encompasses a multi-tude of structurally diverse natural products. The genome of the erythro-mycin-producing strainSaccharopolyspora erythraeacontains 25 secondary
metabolite gene clusters that are mostly considered to be orphan, including
two that are responsible for siderophore assembly.
The aim of this study is to discover and characterize novel energy homeo-stasis-related molecules. We screened stock mouse embryonic stem cells
established using the exchangeable gene trap method, and examined the
effects of deficiency of the target gene on diet and genetic-induced obesity.
Although thiazolidinediones (TZDs) are potent promoters of adipogenesis
in the preadipocyte, they induce apoptosis in several other cell types,
such as cancer cells, endothelial cells and T-lymphocytes. In this study,
we investigated the proapoptotic effect of TZDs in mature 3T3-L1
adipocytes, which express high levels of the peroxisome proliferator-acti-vated receptor-c (PPARc) protein.
Mitochondrial biogenesis, which depends on nuclear as well as mitochon-drial genes, occurs in response to increased cellular ATP demand. The
nuclear transcriptional factors, estrogen-related receptor a (ERRa) and
nuclear respiratory factors 1 and 2, are associated with the coordination of
the transcriptional machinery governing mitochondrial biogenesis
c-Type cytochromes require specific post-translational protein systems,
which vary in different organisms, for the characteristic covalent attach-ment of heme to the cytochrome polypeptide. Cytochromec biogenesis
System II, found in chloroplasts and many bacteria, comprises four subun-its, two of which (ResB and ResC) are the minimal functional unit.
Nucleotide variations that do not alter the protein-coding sequence have
been routinely considered as neutral. In light of the developments we have
seen over the last decade or so in the RNA processing and translational
field, it would be proper when assessing these variants to ask if this change
is neutral, good or bad.
What makes a nucleotide sequence an exon (or an intron) is a question
that still lacks a satisfactory answer. Indeed, most eukaryotic genes are full
of sequences that look like perfect exons, but which are nonetheless
ignored by the splicing machinery (hence the name ‘pseudoexons’).
Following the original reports of pre-mRNA splicing in 1977, it was
quickly realized that splicing together of different combinations of splice
sites – alternative splicing– allows individual genes to generate more than
one mRNA isoform. The full extent of alternative splicing only began to
be revealed once large-scale genome and transcriptome sequencing projects
began, rapidly revealing that alternative splicing is the rule rather than the
The retroviral life cycle requires that significant amounts of RNA remain
unspliced and perform several functions in the cytoplasm. Thus, the full-length RNA serves both the viral genetic material that will be encapsulated
in viral particles and the mRNA encoding structural and enzymatic pro-teins required for viral replication.
Glutaminase from Micrococcus luteusK-3 [Micrococcusglutaminase
(Mglu); 456 amino acid residues (aa); 48 kDa] is a salt-tolerant enzyme. Our
previous study determined the structure of its major 42-kDa fragment. Here,
using new crystallization conditions, we determined the structures of the
intact enzyme in the presence and absence of its product l-glutamate and its
activator Tris, which activates the enzyme by sixfold.
Realistic quantitative models require data from many laboratories. There-fore, standardization of experimental systems and assay conditions is crucial.
Moreover, standards should be representative of thein vivoconditions. How-ever, most often, enzyme–kinetic parameters are measured under assay con-ditions that yield the maximum activity of each enzyme.