Global in vivo terminal amino acid labeling for exploring differential expressed proteins induced by dialyzed serum cultivation

The Analyst ◽  
2014 ◽  
Vol 139 (18) ◽  
pp. 4497-4504 ◽  
Author(s):  
Li-Qi Xie ◽  
Ai-Ying Nie ◽  
Shu-Jun Yang ◽  
Chao Zhao ◽  
Lei Zhang ◽  
...  

An accurate and high throughput isobaric MS2 quantification strategy based on metabolic labeling and trypsin digestion.

1998 ◽  
Vol 159 (1) ◽  
pp. 93-102 ◽  
Author(s):  
U Ritzel ◽  
U Leonhardt ◽  
M Ottleben ◽  
A Ruhmann ◽  
K Eckart ◽  
...  

Glucagon-like peptide-1 (GLP-1) is the most potent endogenous insulin-stimulating hormone. In the present study the plasma stability and biological activity of a GLP-1 analog, [Ser]GLP-1(7-36)amide, in which the second N-terminal amino acid alanine was replaced by serine, was evaluated in vitro and in vivo. Incubation of GLP-1 with human or rat plasma resulted in degradation of native GLP-1(7-36)amide to GLP-1(9-36)amide, while [Ser]GLP-1(7-36)amide was not significantly degraded by plasma enzymes. Using glucose-responsive HIT-T15 cells, [Ser]GLP-1(7-36)amide showed strong insulinotropic activity, which was inhibited by the specific GLP-1 receptor antagonist exendin-4(9-39)amide. Simultaneous i.v. injection of [Ser]GLP-1(7-36)amide and glucose in rats induced a twofold higher increase in plasma insulin levels than unmodified GLP-1(7-36)amide with glucose and a fivefold higher increase than glucose alone. [Ser]GLP-1(7-36)amide induced a 1.5-fold higher increase in plasma insulin than GLP-1(7-36)amide when given 1 h before i.v. application of glucose. The insulinotropic effect of [Ser]GLP-1(7-36)amide was suppressed by i.v. application of exendin-4(9-39)amide. The present data demonstrate that replacement of the second N-terminal amino acid alanine by serine improves the plasma stability of GLP-1(7-36)amide. The insulinotropic action in vitro and in vivo was not impaired significantly by this modification.


1997 ◽  
Vol 136 (2) ◽  
pp. 251-269 ◽  
Author(s):  
Peng Chen ◽  
Stephanie K. Sapperstein ◽  
Jonathan D. Choi ◽  
Susan Michaelis

The Saccharomyces cerevisiae mating pheromone a-factor is a prenylated and carboxyl methylated extracellular peptide signaling molecule. Biogenesis of the a-factor precursor proceeds via a distinctive multistep pathway that involves COOH-terminal modification, NH2-terminal proteolysis, and a nonclassical export mechanism. In this study, we examine the formation and fate of a-factor biosynthetic intermediates to more precisely define the events that occur during a-factor biogenesis. We have identified four distinct a-factor biosynthetic intermediates (P0, P1, P2, and M) by metabolic labeling, immunoprecipitation, and SDSPAGE. We determined the biochemical composition of each by defining their NH2-terminal amino acid and COOH-terminal modification status. Unexpectedly, we discovered that not one, but two NH2-terminal cleavage steps occur during the biogenesis of a-factor. In addition, we have shown that COOH-terminal prenylation is required for the NH2-terminal processing of a-factor and that all the prenylated a-factor intermediates (P1, P2, and M) are membrane bound, suggesting that many steps of a-factor biogenesis occur in association with membranes. We also observed that although the biogenesis of a-factor is a rapid process, it is inherently inefficient, perhaps reflecting the potential for regulation. Previous studies have identified gene products that participate in the COOH-terminal modification (Ram1p, Ram2p, Ste14p), NH2-terminal processing (Ste24p, Axl1p), and export (Ste6p) of a-factor. The intermediates defined in the present study are discussed in the context of these biogenesis components to formulate an overall model for the pathway of a-factor biogenesis.


1991 ◽  
Vol 278 (2) ◽  
pp. 493-497 ◽  
Author(s):  
P J Jose ◽  
P D Collins ◽  
J A Perkins ◽  
B C Beaubien ◽  
N F Totty ◽  
...  

The intraperitoneal injection of zymosan in the rabbit results in the generation of an inflammatory exudate containing oedema-forming and chemoattractant activities. Previous studies demonstrated the early appearance of the complement fragment C5a, followed by the generation of two mediators related to the cytokine interleukin-8 that were separable by cation-exchange h.p.l.c. N-Terminal amino acid sequencing identified one of these mediators as rabbit interleukin-8. This paper describes the purification of the second cytokine by cation-exchange, gel-filtration and reversed-phase h.p.l.c. The purified material had both oedema-forming and chemoattractant activity when assayed in rabbit skin in vivo. On SDS/PAGE a single 6-8 kDa band was observed and N-terminal amino acid sequencing of the reduced and alkylated protein positively identified 36 amino acids. This sequence revealed the rabbit homologue of melanoma-growth-stimulatory activity. The identification of these two cytokines in vivo will provide an opportunity to investigate the importance of their co-release in the inflammatory process.


F1000Research ◽  
2021 ◽  
Vol 10 ◽  
pp. 3
Author(s):  
Harutyun Sahakian ◽  
Karen Nazarian ◽  
Arcady Mushegian ◽  
Irina Sorokina

Background: Proteins fold robustly and reproducibly in vivo, but many cannot fold in vitro in isolation from cellular components. Despite the remarkable progress that has been achieved by the artificial intelligence approaches in predicting the protein native conformations, the pathways that lead to such conformations, either in vitro or in vivo, remain largely unknown. The slow progress in recapitulating protein folding pathways in silico may be an indication of the fundamental deficiencies in our understanding of folding as it occurs in nature. Here we consider the possibility that protein folding in living cells may not be driven solely by the decrease in Gibbs free energy and propose that protein folding in vivo should be modeled as an active energy-dependent process. The mechanism of action of such a protein folding machine might include direct manipulation of the peptide backbone. Methods: To show the feasibility of a protein folding machine, we conducted molecular dynamics simulations that were augmented by the application of mechanical force to rotate the C-terminal amino acid while simultaneously limiting the N-terminal amino acid movements. Results: Remarkably, the addition of this simple manipulation of peptide backbones to the standard molecular dynamics simulation indeed facilitated the formation of native structures in five diverse alpha-helical peptides. Steric clashes that arise in the peptides due to the forced directional rotation resulted in the behavior of the peptide backbone no longer resembling a freely jointed chain. Conclusions: These simulations show the feasibility of a protein folding machine operating under the conditions when the movements of the polypeptide backbone are restricted by applying external forces and constraints. Further investigation is needed to see whether such an effect may play a role during co-translational protein folding in vivo and how it can be utilized to facilitate folding of proteins in artificial environments.


2020 ◽  
Author(s):  
Harutyun K. Sahakyan ◽  
Karen B. Nazaryan ◽  
Arcady R. Mushegian ◽  
Irina N. Sorokina

AbstractProteins fold robustly and reproducibly in vivo, but many cannot fold in vitro in isolation from cellular components. The pathways to proteins’ native conformations, either in vitro or in vivo, remain largely unknown. The slow progress in recapitulating protein folding pathways in silico may be an indication of the fundamental deficiencies in our understanding of folding as it occurs in nature. Here we consider the possibility that protein folding in living cells may not be driven solely by the decrease in Gibbs free energy and propose that protein folding in vivo should be modeled as an active energy-dependent process. The mechanism of action of such protein folding machine might include direct manipulation of the peptide backbone. To show the feasibility of a protein folding machine, we conducted molecular dynamics simulations that were augmented by the application of mechanical force to rotate the C-terminal amino acid while simultaneously limiting the N-terminal amino acid movements. Remarkably, the introduction of this simple manipulation of peptide backbones to the standard molecular dynamics simulation indeed facilitated the formation of native structures in five diverse alpha-helical peptides. Such effect may play a role during co-translational protein folding in vivo: considering the rotating motion of the tRNA 3’-end in the peptidyltransferase center of the ribosome, it is possible that this motion might introduce rotation to the nascent peptide and influence the peptide’s folding pathway in a way similar to what was observed in our simulations.


1978 ◽  
Vol 173 (3) ◽  
pp. 773-786 ◽  
Author(s):  
K A Bostian ◽  
G F Betts

A method for the purification of yeast K+-activated aldehyde dehydrogenase is presented which can be completed in substantially less time than other published procedures. The enzyme has a different N-terminal amino acid from preparations previously reported, and other small differences in amino acid content. These differences may be the result of differential proteolytic digestion rather than a different protein in vivo. A purification step involves the biospecific adsorption on affinity columns containing immobilized nucleotides in the absence of the substrate aldehyde. Direct binding studies with the coenzyme in the absence of aldehyde reveal 4 NAD sites per tetrameric molecule, each with a dissociation constant of 120 micron. These results conflict with properties of preparations previously reported and may conflict with kinetic models that have aldehyde as the leading substrate. Binding to Blue Dextran affinity columns suggests the presence of a dinucleotide fold in common with other dehydrogenases and kinases.


Author(s):  
Chi-Ming Wei ◽  
Margaret Hukee ◽  
Christopher G.A. McGregor ◽  
John C. Burnett

C-type natriuretic peptide (CNP) is a newly identified peptide that is structurally related to atrial (ANP) and brain natriuretic peptide (BNP). CNP exists as a 22-amino acid peptide and like ANP and BNP has a 17-amino acid ring formed by a disulfide bond. Unlike these two previously identified cardiac peptides, CNP lacks the COOH-terminal amino acid extension from the ring structure. ANP, BNP and CNP decrease cardiac preload, but unlike ANP and BNP, CNP is not natriuretic. While ANP and BNP have been localized to the heart, recent investigations have failed to detect CNP mRNA in the myocardium although small concentrations of CNP are detectable in the porcine myocardium. While originally localized to the brain, recent investigations have localized CNP to endothelial cells consistent with a paracrine role for CNP in the control of vascular tone. While CNP has been detected in cardiac tissue by radioimmunoassay, no studies have demonstrated CNP localization in normal human heart by immunoelectron microscopy.


1973 ◽  
Vol 74 (2) ◽  
pp. 226-236 ◽  
Author(s):  
Michel Chrétien ◽  
Claude Gilardeau

ABSTRACT A protein isolated from ovine pituitary glands has been purified, and its homogeneity assessed by NH2- and COOH-terminal amino acid determination, ultracentrifugation studies, and polyacrylamide gel electrophoresis after carboxymethylation. Its chemical and immunochemical properties are closely similar to those of beef and pork neurophysins, less similar to those of human neurophysins. It contains no tryptophan (like other neurophysins) or histidine (like all except bovine neurophysin-I and human neurophysins). It has alanine at the NH2-terminus and valine at the COOH-terminus. Its amino acid composition is similar to, but not identical with those of porcine and bovine neurophysins.


1980 ◽  
Vol 45 (4) ◽  
pp. 1144-1154 ◽  
Author(s):  
Miroslav Baudyš ◽  
Helena Keilová ◽  
Vladimír Kostka

To determine the primary structure of the C-terminal part of the molecule of chicken pepsinogen the tryptic, chymotryptic and thermolytic digest of the protein were investigated and peptides derived from this region were sought. These peptides permitted the following 21-residue C-terminal sequence to be determined: ...Ile-Arg-Glu-Tyr-Tyr-Val-Ile-Phe-Asp-Arg-Ala-Asn-Asn-Lys-Val-Gly-Leu-Ser-Pro-Leu-Ser.COOH. A comparison of this structure with the C-terminal sequential regions of the other acid proteases shows a high degree of homology between chicken pepsinogen and these proteases (e.g., the degree of homology with respect to hog pepsinogen and calf prochymosin is about 66%). Additional tryptic peptides, derived from the N-terminal part of the zymogen molecule whose amino acid sequence has been reported before, were also obtained in this study. This sequence was extended by two residues using an overlapping peptide. An ancillary result of this study was the isolation of tryptic peptides derived from other regions of the zymogen molecule.


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