scholarly journals Cyclic enkephalin-deltorphin hybrids containing a carbonyl bridge: structure and opioid activity.

2011 ◽  
Vol 58 (2) ◽  
Author(s):  
Małgorzata Ciszewska ◽  
Katarzyna Ruszczyńska ◽  
Marta Oleszczuk ◽  
Nga N Chung ◽  
Ewa Witkowska ◽  
...  
Keyword(s):  
Dynamical Behavior ◽  
Ring Structure ◽  
Bridge Structure ◽  
Ring Extension ◽  
Small Peptides ◽  
Mouse Vas Deferens ◽  
C Terminus ◽  
Synthetic Procedure ◽  
Fmoc Group ◽  
Dibasic Amino Acids

Six hybrid N-ureidoethylamides of octapeptides in which an N-terminal cyclic structure related to enkephalin was elongated by a C-terminal fragment of deltorphin were synthesized on MBHA resin. The synthetic procedure involved deprotection of Boc groups with HCl/dioxane and cleavage of the peptide resin with 45 % TFA in DCM. d-Lys and d-Orn were incorporated in position 2, and Lys, Orn, Dab, or Dap in position 5. The side chains of the dibasic amino function were protected with the Fmoc group. This protection was removed by treatment with 55 % piperidine in DMF, and cyclization was achieved by treatment with bis-(4-nitrophenyl)carbonate. Using various combinations of dibasic amino acids, peptides containing a 17-, 18-, 19- or 20-membered ring structure were obtained. The peptides were tested in the guinea-pig ileum (GPI) and mouse vas deferens (MVD) assays. Diverse opioid activities were observed, depending on the size of the ring. Extension of the enkephalin sequence at the C-terminus by a deltorphin fragment resulted in a change of receptor selectivity in favor of the δ receptor. The conformational propensities of selected peptides were determined using the EDMC method in conjunction with data derived from NMR experiments carried out in water. This approach allowed proper examination of the dynamical behavior of these small peptides. The results were compared with those obtained earlier with corresponding N-(ureidoethyl)pentapeptide amides.

Affinity Tags for Protein Purification

2020 ◽  
Vol 21 (8) ◽  
pp. 821-830
Author(s):  
Vibhor Mishra
Keyword(s):  
Protein Purification ◽  
Protein Complexes ◽  
Affinity Purification ◽  
Protein Domain ◽  
Affinity Tag ◽  
Small Peptides ◽  
Affinity Tags ◽  
C Terminus ◽  
Solubility Enhancers ◽  
As Solubility

The affinity tags are unique proteins/peptides that are attached at the N- or C-terminus of the recombinant proteins. These tags help in protein purification. Additionally, some affinity tags also serve a dual purpose as solubility enhancers for challenging protein targets. By applying a combinatorial approach, carefully chosen affinity tags designed in tandem have proven to be very successful in the purification of single proteins or multi-protein complexes. In this mini-review, the key features of the most commonly used affinity tags are discussed. The affinity tags have been classified into two significant categories, epitope tags, and protein/domain tags. The epitope tags are generally small peptides with high affinity towards a chromatography resin. The protein/domain tags often perform double duty as solubility enhancers as well as aid in affinity purification. Finally, protease-based affinity tag removal strategies after purification are discussed.

IRON MAN interacts with BRUTUS to maintain iron homeostasis in Arabidopsis

2021 ◽  
Vol 118 (39) ◽  
pp. e2109063118
Author(s):  
Yang Li ◽  
Cheng Kai Lu ◽  
Chen Yang Li ◽  
Ri Hua Lei ◽  
Meng Na Pu ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Transcription Factors ◽  
Iron Homeostasis ◽  
Fe Deficiency ◽  
Small Peptides ◽  
Interaction Domain ◽  
C Terminus ◽  
Positive Regulators ◽  
Fe Homeostasis ◽  
And Function

IRON MAN (IMA) peptides, a family of small peptides, control iron (Fe) transport in plants, but their roles in Fe signaling remain unclear. BRUTUS (BTS) is a potential Fe sensor that negatively regulates Fe homeostasis by promoting the ubiquitin-mediated degradation of bHLH105 and bHLH115, two positive regulators of the Fe deficiency response. Here, we show that IMA peptides interact with BTS. The C-terminal parts of IMA peptides contain a conserved BTS interaction domain (BID) that is responsible for their interaction with the C terminus of BTS. Arabidopsis thaliana plants constitutively expressing IMA genes phenocopy the bts-2 mutant. Moreover, IMA peptides are ubiquitinated and degraded by BTS. bHLH105 and bHLH115 also share a BID, which accounts for their interaction with BTS. IMA peptides compete with bHLH105/bHLH115 for interaction with BTS, thereby inhibiting the degradation of these transcription factors by BTS. Genetic analyses suggest that bHLH105/bHLH115 and IMA3 have additive roles and function downstream of BTS. Moreover, the transcription of both BTS and IMA3 is activated directly by bHLH105 and bHLH115 under Fe-deficient conditions. Our findings provide a conceptual framework for understanding the regulation of Fe homeostasis: IMA peptides protect bHLH105/bHLH115 from degradation by sequestering BTS, thereby activating the Fe deficiency response.

scholarly journals Group-graded and group-bigraded rings

2015 ◽  
Vol 14 (07) ◽  
pp. 1550100 ◽  
Author(s):  
Mitsuo Hoshino ◽  
Noritsugu Kameyama ◽  
Hirotaka Koga
Keyword(s):  
Multiplicative Group ◽  
Unit Element ◽  
Ring Structure ◽  
Ring Extension ◽  
Graded Ring ◽  
Frobenius Extension

Let I be a nontrivial finite multiplicative group with the unit element e and A = ⨁x∈I Ax an I-graded ring. We construct a Frobenius extension Λ of A and study when the ring extension A of Ae can be a Frobenius extension. Also, formulating the ring structure of Λ, we introduce the notion of I-bigraded rings and show that every I-bigraded ring is isomorphic to the I-bigraded ring Λ constructed above.

Concurrent modifications of the C-terminus and side ring of thiostrepton and their synergistic effects with respect to improving antibacterial activities

2016 ◽  
Vol 3 (4) ◽  
pp. 496-500 ◽  
Author(s):  
Shoufeng Wang ◽  
Qingfei Zheng ◽  
Jianfeng Wang ◽  
Dandan Chen ◽  
Yunsong Yu ◽  
...  
Keyword(s):  
Mutant Strain ◽  
Double Mutant ◽  
Synergistic Effects ◽  
Antibacterial Activities ◽  
Ring Structure ◽  
Quinaldic Acid ◽  
C Terminus ◽  
Double Mutant Strain

Five new C-terminally methylated TSR derivatives that varied in side-ring structure were obtained via the chemical feeding of quinaldic acid analogs to a double-mutant strain ΔtsrB/T.

Receptors for calcitonin, calcitonin gene related peptide, amylin, and adrenomedullin

1995 ◽  
Vol 73 (7) ◽  
pp. 963-967 ◽  
Author(s):  
Roman Muff ◽  
Walter Born ◽  
Jan A. Fischer
Keyword(s):  
Amino Acid ◽  
Disulfide Bridge ◽  
Calcitonin Gene Related Peptide ◽  
Ring Structure ◽  
Cross Reactivity ◽  
Related Peptide ◽  
C Terminus ◽  
Calcitonin Gene ◽  
G Protein Coupled ◽  
Biological Actions

Calcitonin, calcitonin gene related peptide, amylin, and adrenomedullin are structurally related polypeptides characterized by a six or seven amino acid ring structure linked by a disulfide bridge and an amidated C-terminus. They exhibit overlapping biological actions as a result of cross-reactivity between the different receptors. In this article, the respective receptors and G-protein-coupled postreceptor events are reviewed in relation to some of the biological actions of the peptides.Key words: adrenomedullin, amylin, calcitonin gene related peptide, cyclic AMP, receptors.

scholarly journals Phosphorylation and O-GlcNAcylation of the PHF-1 Epitope of Tau Protein Induce Local Conformational Changes of the C-Terminus and Modulate Tau Self-Assembly Into Fibrillar Aggregates

2021 ◽  
Vol 14 ◽  
Author(s):  
François-Xavier Cantrelle ◽  
Anne Loyens ◽  
Xavier Trivelli ◽  
Oliver Reimann ◽  
Clément Despres ◽  
...  
Keyword(s):  
Conformational Changes ◽  
Tau Protein ◽  
Posttranslational Modifications ◽  
Self Assembly ◽  
Critical Role ◽  
Small Peptides ◽  
C Terminus ◽  
The Impact

Phosphorylation of the neuronal microtubule-associated Tau protein plays a critical role in the aggregation process leading to the formation of insoluble intraneuronal fibrils within Alzheimer’s disease (AD) brains. In recent years, other posttranslational modifications (PTMs) have been highlighted in the regulation of Tau (dys)functions. Among these PTMs, the O-β-linked N-acetylglucosaminylation (O-GlcNAcylation) modulates Tau phosphorylation and aggregation. We here focus on the role of the PHF-1 phospho-epitope of Tau C-terminal domain that is hyperphosphorylated in AD (at pS396/pS404) and encompasses S400 as the major O-GlcNAc site of Tau while two additional O-GlcNAc sites were found in the extreme C-terminus at S412 and S413. Using high resolution NMR spectroscopy, we showed that the O-GlcNAc glycosylation reduces phosphorylation of PHF-1 epitope by GSK3β alone or after priming by CDK2/cyclin A. Furthermore, investigations of the impact of PTMs on local conformation performed in small peptides highlight the role of S404 phosphorylation in inducing helical propensity in the region downstream pS404 that is exacerbated by other phosphorylations of PHF-1 epitope at S396 and S400, or O-GlcNAcylation of S400. Finally, the role of phosphorylation and O-GlcNAcylation of PHF-1 epitope was probed in in-vitro fibrillization assays in which O-GlcNAcylation slows down the rate of fibrillar assembly while GSK3β phosphorylation stimulates aggregation counteracting the effect of glycosylation.

scholarly journals Differential expression and seasonal modulation of VGF peptides in sheep pituitary

2005 ◽  
Vol 186 (1) ◽  
pp. 97-107 ◽  
Author(s):  
Carla Brancia ◽  
Paola Nicolussi ◽  
Pietro Cappai ◽  
Giorgio La Corte ◽  
Roberta Possenti ◽  
...  
Keyword(s):  
Subcellular Location ◽  
Relative Molecular Mass ◽  
Cell Type ◽  
Small Peptides ◽  
Peptide Profile ◽  
C Terminus ◽  
Cell Type Specific ◽  
Endocrine Cell Type ◽  
Female Sheep ◽  
Inducible Gene

The inducible gene vgf and its peptide products are relevant to the neuroendocrine regulation of homeostasis and reproduction in rodents. We show here that in the anterior pituitary of female sheep the somatotrope, gonadotrope, and lactotrope/thyrotrope cell populations each expressed vgf mRNA, but displayed a distinct profile of VGF immunoreactive peptides. ProVGF C-terminus and VGF443–588 immunoreactivities were found in lactotropes and thyrotropes, often in a subcellular location restricted to the Golgi area and suggestive of rapid peptide (or proVGF) release upon biosynthesis, while high molecular weight bands consistent with proVGF were shown in pituitary extracts. Distinct seasonal changes were revealed, proVGF C-terminus immunoreactive cells being largely identified as lactotropes during the summer (83.7 ± 2.1% (mean ±s.e.m.) versus 27.0 ± 1.9% during the winter), as opposed to thyrotropes during the winter (73.0 ± 1.9% versus 16.3 ± 2.1% during the summer). Conversely, antisera to peptides adjacent to the ‘Arg-Pro-Arg’ cleavage site, and to the VGF553–555 N-terminus of the proVGF-derived peptide V, selectively labeled gonadotropes, indicating processing to small peptides not retaining the proVGF C-terminus in such cells. Finally, a peptide related to the VGF4–240 region was immunostained in somatotropes, shown in a Western blot as a band of relative molecular mass of approximately 16 000. In conclusion, a complex, endocrine cell-type-specific processing of proVGF was revealed. Further to the known inducibility of vgf mRNA upon a range of stimuli, discreet, selective modulations of VGF-peptide profile/s are suggested, possibly involved in specific neuro/endocrine or modulatory mechanisms.

scholarly journals Cloning, sequencing and heterologous expression of the gene for lupanine hydroxylase, a quinocytochrome c from a Pseudomonas sp.

2002 ◽  
Vol 367 (2) ◽  
pp. 483-489 ◽  
Author(s):  
David J. HOPPER ◽  
Mustak A. KADERBHAI ◽  
Shirley A. MARRIOTT ◽  
Michael YOUNG ◽  
Jerzy ROGOZINSKI
Keyword(s):  
Cytochrome C ◽  
Transcriptional Control ◽  
Signal Sequence ◽  
Consensus Sequence ◽  
Ring Structure ◽  
Pseudomonas Sp ◽  
Chromosomal Dna ◽  
Gene Encoding ◽  
Terminal Domain ◽  
C Terminus

The gene encoding the enzyme lupanine hydroxylase was isolated by PCR using chromosomal DNA from a lupanine-utilizing Pseudomonas sp. as template and primers based on the sequences of the N- and C-termini of the purified protein. The derived sequence for the mature gene product gave a protein with an Mr of 72256, in good agreement with the value found by SDS/PAGE of the pure enzyme, and contained the sequences of several peptides obtained after endoproteinase Lys-C digestion of the pure enzyme. The gene, under the transcriptional control of a phoA promotor and with the Escherichia coli alkaline phosphatase signal sequence, was expressed in E. coli containing a plasmid expressing the genes for cytochrome c maturation proteins constitutively. Haem-containing inactive protein in inclusion bodies was renatured and reactivated with pyrroloquinoline quinone (PQQ) and Ca2+ to give active enzyme. The lupanine hydroxylase (luh) gene coded for a protein with a cleavable 26-residue signal sequence at its N-terminus, required for the transport of the enzyme to its periplasmic location. Analysis of the protein sequence showed that it contains two domains, a large PQQ-binding N-terminal domain and a smaller cytochrome c C-terminal domain. Comparison of the derived sequence with those of other proteins showed considerable similarity with other quino(haemo)proteins, including alcohol dehydrogenases from a variety of bacteria. The PQQ-binding domain sequence contains W motifs, characteristic of the eight-bladed ‘propeller’ structure of methanol dehydrogenase, but lacks the unusual disulphide ring structure formed from two adjacent cysteines seen in this enzyme. The C-terminus shares some similarity with bacterial cytochrome c and includes the haem-binding consensus sequence CXXCH.

scholarly journals Laccaria bicolor MiSSP8 is a small-secreted protein decisive for the establishment of the ectomycorrhizal symbiosis

2017 ◽  
Author(s):  
Clément Pellegrin ◽  
Yohann Daguerre ◽  
Joske Ruytinx ◽  
Frédéric Guinet ◽  
Minna Kemppainen ◽  
...  
Keyword(s):  
Secreted Protein ◽  
Small Peptides ◽  
Ectomycorrhizal Symbiosis ◽  
C Terminus ◽  
Repetitive Motif ◽  
Set Up ◽  
Host Metabolism ◽  
Soil Borne Fungi

AbstractThe ectomycorrhizal symbiosis is a predominant tree-microbe interaction in forest ecosystems sustaining tree growth and health. Its establishment and functioning implies a long-term and intimate relationship between the soil-borne fungi and the roots of trees. Mycorrhiza-induced Small Secreted Proteins (MiSSPs) are hypothesized as keystone symbiotic proteins, required to set up the symbiosis by modifying the host metabolism and/or building the symbiotic interfaces.L. bicolor MiSSP8 is the third most highly induced MiSSPs in symbiotic tissues and it is also expressed in fruiting bodies. The MiSSP8-RNAi knockdown mutants are strongly impaired in their mycorrhization ability with Populus, with the lack of fungal mantle and Hartig net development due to a lack of hyphal aggregation. MiSSP8 C-terminus displays a repetitive motif containing a kexin cleavage site, recognized by KEX2 in vitro. This suggests MiSSP8 protein might be cleaved into small peptides. Moreover, the MiSSP8 repetitive motif is found in other proteins predicted secreted by both saprotrophic and ectomycorrhizal fungi. Thus, our data indicate that MiSSP8 is a small-secreted protein involved at early stages of ectomycorrhizal symbiosis, likely by regulating hyphal aggregation and pseudoparenchyma formation.

Identification of small peptides mimicking the R2 C -terminus of Mycobacterium tuberculosis ribonucleotide reductase

2010 ◽  
Vol 16 (3) ◽  
pp. 159-164 ◽  
Author(s):  
Daniel J. Ericsson ◽  
Johanna Nurbo ◽  
Daniel Muthas ◽  
Kalle Hertzberg ◽  
Gunnar Lindeberg ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Ribonucleotide Reductase ◽  
Small Peptides ◽  
C Terminus
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