Ein NADH‐Umsatz von 741 min−1 wird bei der Oxidation von Ethan zu Ethanol mit einer „konstruierten“ Form der Häm‐Monooxygenase Cytochrom P450cam erreicht. Das ist das erste Beispiel für eine solche Aktivität eines P450‐Enzyms (die GC‐Analyse ist gezeigt). Ethanol entsteht mit 78 min−1 (10.5 % Kupplung). Die Mutante ist ohne Substrat zu etwa 45 % im High‐Spin‐Zustand, was sie zu einer nützlichen Plattform für Struktur‐Funktions‐Studien an P450 macht.
The homeostasis of protein palmitoylation and depalmitoylation is essential for proper physiological functions in various tissues, in particular the central nervous system (CNS). The dysfunction of PPT1 (PPT1-KI, infantile neuronal ceroid lipofuscinosis [INCL] mouse model), which catalyze the depalmitoylation process, results in serious neurodegeneration accompanied by severe astrogliosis in the brain. Endeavoring to determine critical factors that might account for the pathogenesis in CNS by palm-proteomics, glial fibrillary acidic protein (GFAP) was spotted, indicating that GFAP is probably palmitoylated. Questions concerning if GFAP is indeed palmitoylated in vivo and how palmitoylation of GFAP might participate in neural pathology remain unexplored and are waiting to be investigated. Here we show that GFAP is readily palmitoylated in vitro and in vivo; specifically, cysteine-291 is the unique palmitoylated residue in GFAP. Interestingly, it was found that palmitoylated GFAP promotes astrocyte proliferation in vitro. Furthermore, we showed that PPT1 depalmitoylates GFAP, and the level of palmitoylated GFAP is overwhelmingly up-regulated in PPT1-knockin mice, which lead us to speculate that the elevated level of palmitoylated GFAP might accelerate astrocyte proliferation in vivo and ultimately led to astrogliosis in INCL. Indeed, blocking palmitoylation by mutating cysteine-291 into alanine in GFAP attenuate astrogliosis, and remarkably, the concurrent neurodegenerative pathology in PPT1-knockin mice. Together, these findings demonstrate that hyperpalmitoylated GFAP plays critical roles in regulating the pathogenesis of astrogliosis and neurodegeneration in the CNS, and most importantly, pinpointing that cysteine-291 in GFAP might be a valuable pharmaceutical target for treating INCL and other potential neurodegenerative diseases.
Tuberculosis (TB) remains to be a major infectious disease throughout the world. However, the current vaccine for TB has variable protective efficacy, and there is no commercially available serodiagnostic test for this disease with acceptable sensitivity and specificity for routine laboratory use. One of the potential strategies in developing a new diagnostic method and in improving the TB vaccine involves the identification of novel antigenic candidates. This paper aims to identify systematically the novel antigenic proteins with the greatest potential as protective or diagnostic antigens by using the differential response of Mycobacterium tuberculosis proteins to serum from TB patients and healthy individuals. Approximately 87% of the open reading frames of M. tuberculosis were successfully cloned into IPTG-inducible expression vectors. The clone sets were expressed in Escherichia coli, purified under denatured conditions, and tested for antigenicity using a mixture of sera from 15 TB patients. Out of the 3480 proteins screened, 249 proteins had significant reactions with the serum samples. Among the 249 proteins, 20 proteins were identified as most reactive. Compared with the commercial test kits, 3 novel antigens from the top 20 proteins, namely, Rv1987, Rv3807c, and Rv3887c, provided better sensitivity and accuracy. These newly identified antigenic proteins may be used as candidates for serodiagnostic application and vaccine development. Overall, this study's findings may serve as an essential reference for developing new TB diagnostic methods and more effective tuberculosis vaccines.
Background:
The homeostasis of palmitoylation and depalmitoylation is
involved in various cellular processes, the disruption of which induces severe
physiological consequences. Acyl-protein thioesterase (APT) and palmitoyl-protein
thioesterases (PPT) catalyze the depalmitoylation process. The natural mutation in
human PPT1 caused neurodegenerative disease, yet the understanding of APT1
remains to be elucidated. While the deletion of APT1 in mice turned out to be potentially
embryonically lethal, the decoding of its function strictly relied on the identification of its
substrates.
Objective:
To determine the potential substrates of APT1 by using the generated
human APT1 knockout cell line.
Methods :
The combined techniques of palmitoyl-protein enrichment and massspectrometry
were used to analyze the different proteins. Palmitoyl-proteins both in
HEK293T and APT1-KO cells were extracted by resin-assisted capture (RAC) and data
independent acquisition (DIA) quantitative method of proteomics for data collection.
Results:
In total, 382 proteins were identified. The gene ontology classification
segregated these proteins into diverse biological pathways e.g. endoplasmic reticulum
process and ubiquitin-mediated proteolysis. A few potential substrates were selected for
verification; indeed, major proteins were palmitoylated. Importantly, their levels of
palmitoylation were clearly changed in APT1-KO cells. Interestingly, the proliferation of
APT1-KO cells escalated dramatically as compared to that of the WT cells, which could
be rescued by APT1 overexpression.
Conclusion:
Our study provides a large scale of potential substrates of APT1, thus
facilitating the understanding of its intervened molecular functions.
Background: Last-minute travellers (LMTs) present challenges for health care providers because they may have insufficient time for recommended vaccinations or pre-travel preparation. Our objective was to obtain a better understanding of LMTs in order to help travel medicine providers develop improved strategies to decrease the number of LMTs and potentially reduce travel-related morbidity.
Methods:We defined LMTs as travellers with a departure date of 7 days or fewer from the medical encounter. We analysed the characteristics and health preparation of 12 494 LMTs who presented to a network of US clinical practices Results: LMTs comprised 16% of all travellers. More LMTs than non-LMTs travelled for business or to visit friends and relatives (VFR) (26% vs 16% and 15% vs 8%, respectively; P< 0.0001). More LMTs also travelled for longer than 1 month (27% vs 21%; P<0.0001) and visited only urban areas (40% vs 29%; P<0.0001). At least one travel vaccine was deferred by 18% of LMTs because of insufficient time before departure. Vaccines that required multiple vaccinations, For Permissions, please journals.permissions@oup.com such as Japanese encephalitis and rabies, were the most likely to be deferred because of time constraints.
Conclusion:Interventions to improve the timing of pre-travel health consultations should be developed, particularly for business and VFR travellers. Recently endorsed accelerated vaccine schedules for Japanese encephalitis and rabies may help some LMTs receive protection against these infections despite late presentation for pre-travel health care.
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