scholarly journals Hydrolysis of a second Asp-Pro site at the N-terminus of NOTCH3 in inherited vascular dementia

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Xiaojie Zhang ◽  
Soo Jung Lee ◽  
Michael M. Wang
Keyword(s):  
Cerebral Arteries ◽  
Peptide Bond ◽  
Vascular Disorder ◽  
Peptide Bonds ◽  
Control Brain ◽  
Biochemical Level ◽  
High Level ◽  
And Control ◽  
Hydrolysis Of ◽  
Monospecific Antibodies

AbstractCerebrovascular pathology at the biochemical level has been informed by the study of cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL), a vascular disorder caused by NOTCH3 mutations. Previous work in CADASIL described N-terminal proteolysis of NOTCH3 generated by specific non-enzymatic cleavage of the first Asp-Pro sequence of the protein. Here, we investigated whether the second Asp-Pro peptide bond (residues 121–122) of NOTCH3 is cleaved in CADASIL. Monospecific antibodies were generated that recognize the neo-epitope predicted to be generated by cleavage after Asp121. These antibodies were used to localize cleavage events at Asp121 in post-mortem CADASIL and control brain tissue and to investigate factors that regulate cleavage at Asp121. We report that cleavage at Asp121 occurs at a high level in the arterial media of CADASIL cerebral arteries. Leptomeningeal arteries demonstrated substantially more cleavage product than penetrating arteries in the white matter, and control vessels harbored only a small amount of cleaved NOTCH3. Proteolysis at Asp121 occurred in purified preparations of NOTCH3 ectodomain, was increased by acidic pH and reductive conditions, and required native protein conformation for cleavage. Increasing the concentration of NOTCH3 EGF-like domain protein elevated the level of proteolysis. On the other hand, several polyanionic chemicals potently blocked cleavage at Asp121. These studies demonstrate that the NOTCH3 protein in CADASIL is cleaved in multiple locations at labile Asp-Pro peptide bonds. As such, chronic brain vascular disease, like other neurodegenerative conditions, features proteolysis of pathological proteins at multiple sites which may generate small pathological peptides.

scholarly journals Isolation, purification and structure of exochelin MS, the extracellular siderophore from Mycobacterium smegmatis

1995 ◽  
Vol 305 (1) ◽  
pp. 187-196 ◽  
Author(s):  
G J Sharman ◽  
D H Williams ◽  
D F Ewing ◽  
C Ratledge
Keyword(s):  
Amino Acids ◽  
Mycobacterium Smegmatis ◽  
Methyl Esters ◽  
Three Dimensional ◽  
Iron Chelation ◽  
Peptide Bond ◽  
Exchange Chromatography ◽  
Peptide Bonds ◽  
Hydrolysis Of ◽  
Gallium Complex

The extracellular siderophore from Mycobacterium smegmatis, exochelin MS, was isolated from iron-deficiently grown cultures and purified to > 98% by a combination of ion-exchange chromatography and h.p.l.c. The material is unextractable into organic solvents, is basic (pI = 9.3-9.5), has a lambda max at 420 nm and a probable Ks for Fe3+ of between 10(25) and 10(30). Its structure has been determined by examination of desferri- and ferri-exochelin and its gallium complex. The methods used were electrospray-m.s. and one- and two-dimensional (NOESY, DQF-COSY and TOCSY) 1H n.m.r. The constituent amino acids were examined by chiral g.l.c analysis of N-trifluoroacetyl isopropyl and N-pentafluoropropionyl methyl esters after hydrolysis, and reductive HI hydrolysis, of the siderophore. The exochelin is a formylated pentapeptide: N-(delta-N-formyl,delta N-hydroxy-R-ornithyl) -beta-alaninyl-delta N-hydroxy-R-ornithinyl-R-allo-threoninyl-delta N-hydroxy-S-ornithine. The linkages involving the three ornithine residues are via their delta N(OH) and alpha-CO groups leaving three free alpha-NH2 groups. Although there are two peptide bonds, these involve the three R (D)-amino acids. Thus the molecule has no conventional peptide bond, and this suggests that it will be resistant to peptidase hydrolysis. The co-ordination centre with Fe3+ is hexadenate in an octahedral structure involving the three hydroxamic acid groups. Molecular modelling shows it to have similar features to other ferric trihydroxamate siderophores whose three-dimensional structures have been established. The molecule is shown to have little flexibility around the iron chelation centre, although the terminal (Orn-3) residue, which is not involved in iron binding except at its delta N atom, has more motional freedom.

scholarly journals Recognition of protein-linked glycans as a determinant of peptidase activity

2017 ◽  
Vol 114 (5) ◽  
pp. E679-E688 ◽  
Author(s):  
Ilit Noach ◽  
Elizabeth Ficko-Blean ◽  
Benjamin Pluvinage ◽  
Christopher Stuart ◽  
Meredith L. Jenkins ◽  
...  
Keyword(s):  
Posttranslational Modifications ◽  
Peptide Bond ◽  
Peptidase Activity ◽  
Peptide Bonds ◽  
Crystallographic Structures ◽  
Covalently Linked ◽  
Biochemical Analyses ◽  
Life On Earth ◽  
Glycoprotein Degradation ◽  
Hydrolysis Of

The vast majority of proteins are posttranslationally altered, with the addition of covalently linked sugars (glycosylation) being one of the most abundant modifications. However, despite the hydrolysis of protein peptide bonds by peptidases being a process essential to all life on Earth, the fundamental details of how peptidases accommodate posttranslational modifications, including glycosylation, has not been addressed. Through biochemical analyses and X-ray crystallographic structures we show that to hydrolyze their substrates, three structurally related metallopeptidases require the specific recognition of O-linked glycan modifications via carbohydrate-specific subsites immediately adjacent to their peptidase catalytic machinery. The three peptidases showed selectivity for different glycans, revealing protein-specific adaptations to particular glycan modifications, yet always cleaved the peptide bond immediately preceding the glycosylated residue. This insight builds upon the paradigm of how peptidases recognize substrates and provides a molecular understanding of glycoprotein degradation.

Scandium(iii) triflate-promoted serine/threonine-selective peptide bond cleavage

2017 ◽  
Vol 53 (23) ◽  
pp. 3311-3314 ◽  
Author(s):  
Jizhi Ni ◽  
Youhei Sohma ◽  
Motomu Kanai
Keyword(s):  
Bond Cleavage ◽  
Peptide Bond ◽  
High Conversion ◽  
Selective Hydrolysis ◽  
Conversion Yield ◽  
Peptide Bonds ◽  
Peptide Bond Cleavage ◽  
High Conversion Yield ◽  
Site Selective ◽  
Hydrolysis Of

The site-selective hydrolysis of peptide bonds at Ser and Thr positions was promoted by scandium(iii) triflate with a high conversion yield.

scholarly journals Novel Mechanism of Resistance to Glycopeptide Antibiotics in Enterococcus faecium

2006 ◽  
Vol 281 (43) ◽  
pp. 32254-32262 ◽  
Author(s):  
Julie Cremniter ◽  
Jean-Luc Mainardi ◽  
Nathalie Josseaume ◽  
Jean-Charles Quincampoix ◽  
Lionel Dubost ◽  
...  
Keyword(s):  
Enterococcus Faecium ◽  
Peptide Bond ◽  
Cross Resistance ◽  
Glycopeptide Antibiotics ◽  
Penicillin Binding Proteins ◽  
Gram Positive Bacteria ◽  
High Level ◽  
Hydrolysis Of ◽  
Link Formation ◽  
Level Resistance

Glycopeptides and β-lactams are the major antibiotics available for the treatment of infections due to Gram-positive bacteria. Emergence of cross-resistance to these drugs by a single mechanism has been considered as unlikely because they inhibit peptidoglycan polymerization by different mechanisms. The glycopeptides bind to the peptidyl-d-Ala4-d-Ala5 extremity of peptidoglycan precursors and block by steric hindrance the essential glycosyltransferase and d,d-transpeptidase activities of the penicillin-binding proteins (PBPs). The β-lactams are structural analogues of d-Ala4-d-Ala5 and act as suicide substrates of the d,d-transpeptidase module of the PBPs. Here we have shown that bypass of the PBPs by the recently described β-lactam-insensitive l,d-transpeptidase from Enterococcus faecium (Ldtfm) can lead to high level resistance to glycopeptides and β-lactams. Cross-resistance was selected by glycopeptides alone or serially by β-lactams and glycopeptides. In the corresponding mutants, UDP-MurNAc-pentapeptide was extensively converted to UDP-MurNAc-tetrapeptide following hydrolysis of d-Ala5, thereby providing the substrate of Ldtfm. Complete elimination of d-Ala5, a residue essential for glycopeptide binding, was possible because Ldtfm uses the energy of the l-Lys3-d-Ala4 peptide bond for cross-link formation in contrast to PBPs, which use the energy of the d-Ala4-d-Ala5 bond. This novel mechanism of glycopeptide resistance was unrelated to the previously identified replacement of d-Ala5 by d-Ser or d-lactate.

Non-Communicable Diseases and Global Health Politics

2019 ◽  
pp. 626-659
Author(s):  
Roger Magnusson
Keyword(s):  
Respiratory Diseases ◽  
Communicable Diseases ◽  
World Health ◽  
Global Response ◽  
Non Communicable Diseases ◽  
Health Politics ◽  
Chronic Respiratory Diseases ◽  
Health Organization ◽  
High Level ◽  
And Control

Non-communicable diseases (NCDs), including cardiovascular disease, cancer, chronic respiratory diseases, and diabetes, are responsible for around 70 percent of global deaths each year. This chapter describes how NCDs have become prevalent and critically evaluates global efforts to address NCDs and their risk factors, with a particular focus on the World Health Organization (WHO) and United Nations (UN) system. It explores the factors that have prevented those addressing NCDs from achieving access to resources and a priority commensurate with their impact on people’s lives. The chapter evaluates the global response to NCDs both prior to and since the UN High-Level Meeting on Prevention and Control of Non-communicable Diseases, held in 2011, and considers opportunities for strengthening that response in future.

scholarly journals Boundaryless working hours and recovery in Germany

2021 ◽  
Author(s):  
Laura Vieten ◽  
Anne Marit Wöhrmann ◽  
Alexandra Michel
Keyword(s):  
Working Hours ◽  
Working Time ◽  
Overtime Work ◽  
Psychological Detachment ◽  
Representative Study ◽  
Flexible Working ◽  
Recovery Experiences ◽  
High Level ◽  
And Control ◽  
Extended Work

Abstract Objective Due to recent trends such as globalization and digitalization, more and more employees tend to have flexible working time arrangements, including boundaryless working hours. The aim of this study was to investigate the relationships of various aspects of boundaryless working hours (overtime, Sunday work, and extended work availability) with employees’ state of recovery. Besides, we examined the mediating and moderating role of recovery experiences (psychological detachment, relaxation, mastery, and control) in these relationships. Methods We used data from 8586 employees (48% women; average age of 48 years) who took part in the 2017 BAuA-Working Time Survey, a representative study of the German working population. Regression analyses were conducted to test main effects as well as mediation and moderation. Results Overtime work, Sunday work, and extended work availability were negatively related to state of recovery. Psychological detachment mediated these relationships. Furthermore, we found that relaxation and control mediated the association between extended work availability and state of recovery. However, no relevant moderating effects were found. Conclusions Altogether, our findings indicate that various aspects of boundaryless working hours pose a risk to employees’ state of recovery and that especially psychological detachment is a potential mechanism in these relationships. In addition, the results suggest that a high level of recovery experiences cannot attenuate these negative relationships in leisure time. Therefore, employers and employees alike should try to avoid or minimize boundaryless working hours.

scholarly journals Molecular epidemiology of coxsackievirus A16 circulating in children in Beijing, China from 2010 to 2019

2021 ◽  
Author(s):  
Ya-Fang Hu ◽  
Li-Ping Jia ◽  
Fang-Yuan Yu ◽  
Li-Ying Liu ◽  
Qin-Wei Song ◽  
...  
Keyword(s):  
Molecular Epidemiology ◽  
Evolutionary Rate ◽  
Foot And Mouth Disease ◽  
Recent Common Ancestor ◽  
Rt Pcr ◽  
Coxsackievirus A16 ◽  
Most Recent Common Ancestor ◽  
Etiological Agents ◽  
High Level ◽  
And Control

Abstract Background Coxsackievirus A16 (CVA16) is one of the major etiological agents of hand, foot and mouth disease (HFMD). This study aimed to investigate the molecular epidemiology and evolutionary characteristics of CVA16. Methods Throat swabs were collected from children with HFMD and suspected HFMD during 2010–2019. Enteroviruses (EVs) were detected and typed by real-time reverse transcription-polymerase chain reaction (RT-PCR) and RT-PCR. The genotype, evolutionary rate, the most recent common ancestor, population dynamics and selection pressure of CVA16 were analyzed based on viral protein gene (VP1) by bioinformatics software. Results A total of 4709 throat swabs were screened. EVs were detected in 3180 samples and 814 were CVA16 positive. More than 81% of CVA16-positive children were under 5 years old. The prevalence of CVA16 showed obvious periodic fluctuations with a high level during 2010–2012 followed by an apparent decline during 2013–2017. However, the activities of CVA16 increased gradually during 2018–2019. All the Beijing CVA16 strains belonged to sub-genotype B1, and B1b was the dominant strain. One B1c strain was detected in Beijing for the first time in 2016. The estimated mean evolutionary rate of VP1 gene was 4.49 × 10–3 substitution/site/year. Methionine gradually fixed at site-23 of VP1 since 2012. Two sites were detected under episodic positive selection, one of which (site-223) located in neutralizing linear epitope PEP71. Conclusions The dominant strains of CVA16 belonged to clade B1b and evolved in a fast evolutionary rate during 2010–2019 in Beijing. To provide more favorable data for HFMD prevention and control, it is necessary to keep attention on molecular epidemiological and evolutionary characteristics of CVA16.

Sign in / Sign up

Export Citation Format

Share Document