scholarly journals The N-terminus of IFT46 mediates intraflagellar transport of outer arm dynein and its cargo-adaptor ODA16

2017 ◽  
Vol 28 (18) ◽  
pp. 2420-2433 ◽  
Author(s):  
Yuqing Hou ◽  
George B. Witman
Keyword(s):  
Amino Acids ◽  
Fusion Protein ◽  
Intraflagellar Transport ◽  
Critical Importance ◽  
C Terminus ◽  
N Terminus ◽  
Dynein Arms

Cilia are assembled via intraflagellar transport (IFT). The IFT machinery is composed of motors and multisubunit particles, termed IFT-A and IFT-B, that carry cargo into the cilium. Knowledge of how the IFT subunits interact with their cargo is of critical importance for understanding how the unique ciliary domain is established. We previously reported a Chlamydomonas mutant, ift46-1, that fails to express the IFT-B protein IFT46, has greatly reduced levels of other IFT-B proteins, and assembles only very short flagella. A spontaneous suppression of ift46-1 restored IFT-B levels and enabled growth of longer flagella, but the flagella lacked outer dynein arms. Here we show that the suppression is due to insertion of the transposon MRC1 into the ift46-1 allele, causing the expression of a fusion protein including the IFT46 C-terminal 240 amino acids. The IFT46 C-terminus can assemble into and stabilize IFT-B but does not support transport of outer arm dynein into flagella. ODA16, a cargo adaptor specific for outer arm dynein, also fails to be imported into the flagella in the absence of the IFT46 N-terminus. We conclude that the IFT46 N-terminus, ODA16, and outer arm dynein interact for IFT of the latter.

A fusion protein with improved thrombolytic effect and low bleeding risk

2009 ◽  
Vol 102 (12) ◽  
pp. 1194-1203 ◽  
Author(s):  
Lisheng Wang ◽  
Qinglin Zhang ◽  
Yide Qin ◽  
Chutse Wu ◽  
Xiudong Wang ◽  
...  
Keyword(s):  
Fusion Protein ◽  
Anticoagulant Activity ◽  
Bleeding Risk ◽  
Fibrin Clot ◽  
Clot Lysis ◽  
Recognition Sequence ◽  
Linker Peptide ◽  
C Terminus ◽  
N Terminus

SummaryTo resolve the therapeutic dilemma between efficacy of thrombolysis and bleeding risk associated with the use of a combination of thrombolytic and anticoagulant treatments, we created a fusion protein. Staphylokinase was fused to the N-terminus of hirudin using thrombin recognition sequence as linker peptide, resulting in a fusion protein STH.We hypothesised that STH would be cleaved by thrombin at the thrombus site, releasing staphylokinase and hirudin to perform bifunctionally, and attenuating bleeding risk. SDS-PAGE andWestern blot analyses indicated that the linker peptide could be specially recognised and cleaved by thrombin. Amidolytic and thromboelastogram assays showed that the N-terminus of hirudin in STH was blocked by staphylokinase and linker peptide, impeding hirudin’s anticoagulant activity. Once cleaved, STH displayed 35.7% of the anticoagulant activity of equimolar hirudin and exhibited anticoagulant effects in the fibrin clot lysis assay.Thrombin-binding and fibrin clot lysis assays showed that the C-terminus of hirudin retained its high affinity for thrombin. Moreover, STH showed improved thrombolytic effects and a lower bleeding risk in animals. Thus, STH may have the capacity to perform bifunctionally and release anticoagulant activity in a thrombus-targeted manner in vivo, which may reduce the bleeding risk that often accompanies high thrombolytic efficacy in the treatment of thromboembolic diseases.

scholarly journals The Extracellular Transport Signal of the Vibrio cholerae Endochitinase (ChiA) Is a Structural Motif Located between Amino Acids 75 and 555

2002 ◽  
Vol 184 (8) ◽  
pp. 2225-2234 ◽  
Author(s):  
Jason P. Folster ◽  
Terry D. Connell
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Vibrio Cholerae ◽  
Structural Information ◽  
Amino Acid Sequences ◽  
Structural Motif ◽  
Terminal Branch ◽  
C Terminus ◽  
N Terminus ◽  
Extracellular Transport

ABSTRACT ChiA, an 88-kDa endochitinase encoded by the chiA gene of the gram-negative enteropathogen Vibrio cholerae, is secreted via the eps-encoded main terminal branch of the general secretory pathway (GSP), a mechanism which also transports cholera toxin. To localize the extracellular transport signal of ChiA that initiates transport of the protein through the GSP, a chimera comprised of ChiA fused at the N terminus with the maltose-binding protein (MalE) of Escherichia coli and fused at the C terminus with a 13-amino-acid epitope tag (E-tag) was expressed in strain 569B(chiA::Kanr), a chiA-deficient but secretion-competent mutant of V. cholerae. Fractionation studies revealed that blockage of the natural N terminus and C terminus of ChiA did not prevent secretion of the MalE-ChiA-E-tag chimera. To locate the amino acid sequences which encoded the transport signal, a series of truncations of ChiA were engineered. Secretion of the mutant polypeptides was curtailed only when ChiA was deleted from the N terminus beyond amino acid position 75 or from the C terminus beyond amino acid 555. A mutant ChiA comprised of only those amino acids was secreted by wild-type V. cholerae but not by an epsD mutant, establishing that amino acids 75 to 555 independently harbored sufficient structural information to promote secretion by the GSP of V. cholerae. Cys77 and Cys537, two cysteines located just within the termini of ChiA(75-555), were not required for secretion, indicating that those residues were not essential for maintaining the functional activity of the ChiA extracellular transport signal.

scholarly journals Insight from TonB Hybrid Proteins into the Mechanism of Iron Transport through the Outer Membrane

2008 ◽  
Vol 190 (11) ◽  
pp. 4001-4016 ◽  
Author(s):  
Wallace A. Kaserer ◽  
Xiaoxu Jiang ◽  
Qiaobin Xiao ◽  
Daniel C. Scott ◽  
Matthew Bauler ◽  
...  
Keyword(s):  
Amino Acids ◽  
Outer Membrane ◽  
Cell Envelope ◽  
Outer Membrane Proteins ◽  
Binding Motif ◽  
Inner Membrane ◽  
E Coli ◽  
Hybrid Proteins ◽  
C Terminus ◽  
N Terminus

ABSTRACT We created hybrid proteins to study the functions of TonB. We first fused the portion of Escherichia coli tonB that encodes the C-terminal 69 amino acids (amino acids 170 to 239) of TonB downstream from E. coli malE (MalE-TonB69C). Production of MalE-TonB69C in tonB + bacteria inhibited siderophore transport. After overexpression and purification of the fusion protein on an amylose column, we proteolytically released the TonB C terminus and characterized it. Fluorescence spectra positioned its sole tryptophan (W213) in a weakly polar site in the protein interior, shielded from quenchers. Affinity chromatography showed the binding of the TonB C-domain to other proteins: immobilized TonB-dependent (FepA and colicin B) and TonB-independent (FepAΔ3-17, OmpA, and lysozyme) proteins adsorbed MalE-TonB69C, revealing a general affinity of the C terminus for other proteins. Additional constructions fused full-length TonB upstream or downstream of green fluorescent protein (GFP). TonB-GFP constructs had partial functionality but no fluorescence; GFP-TonB fusion proteins were functional and fluorescent. The activity of the latter constructs, which localized GFP in the cytoplasm and TonB in the cell envelope, indicate that the TonB N terminus remains in the inner membrane during its biological function. Finally, sequence analyses revealed homology in the TonB C terminus to E. coli YcfS, a proline-rich protein that contains the lysin (LysM) peptidoglycan-binding motif. LysM structural mimicry occurs in two positions of the dimeric TonB C-domain, and experiments confirmed that it physically binds to the murein sacculus. Together, these findings infer that the TonB N terminus remains associated with the inner membrane, while the downstream region bridges the cell envelope from the affinity of the C terminus for peptidoglycan. This architecture suggests a membrane surveillance model of action, in which TonB finds occupied receptor proteins by surveying the underside of peptidoglycan-associated outer membrane proteins.

scholarly journals Localization of Functional Domains of the Mitogenic Toxin of Pasteurella multocida

2001 ◽  
Vol 69 (12) ◽  
pp. 7839-7850 ◽  
Author(s):  
Gillian D. Pullinger ◽  
R. Sowdhamini ◽  
Alistair J. Lax
Keyword(s):  
Amino Acids ◽  
Fusion Proteins ◽  
Pasteurella Multocida ◽  
Transmembrane Domain ◽  
Polyclonal Antibodies ◽  
Full Length ◽  
Cell Binding ◽  
Terminal Fragment ◽  
C Terminus ◽  
N Terminus

ABSTRACT The locations of the catalytic and receptor-binding domains of thePasteurella multocida toxin (PMT) were investigated. N- and C-terminal fragments of PMT were cloned and expressed as fusion proteins with affinity tags. Purified fusion proteins were assessed in suitable assays for catalytic activity and cell-binding ability. A C-terminal fragment (amino acids 681 to 1285) was catalytically active. When microinjected into quiescent Swiss 3T3 cells, it induced changes in cell morphology typical of toxin-treated cells and stimulated DNA synthesis. An N-terminal fragment with a His tag at the C terminus (amino acids 1 to 506) competed with full-length toxin for binding to surface receptors and therefore contains the cell-binding domain. The inactive mutant containing a mutation near the C terminus (C1165S) also bound to cells in this assay. Polyclonal antibodies raised to the N-terminal PMT region bound efficiently to full-length native toxin, suggesting that the N terminus is surface located. Antibodies to the C terminus of PMT were microinjected into cells and inhibited the activity of toxin added subsequently to the medium, confirming that the C terminus contains the active site. Analysis of the PMT sequence predicted a putative transmembrane domain with predicted hydrophobic and amphipathic helices near the N terminus over the region of homology to the cytotoxic necrotizing factors. The C-terminal end of PMT was predicted to be a mixed α/β domain, a structure commonly found in catalytic domains. Homology to proteins of known structure and threading calculations supported these assignments.

scholarly journals Tolerance of the Ralstonia eutropha Class I Polyhydroxyalkanoate Synthase for Translational Fusions to Its C Terminus Reveals a New Mode of Functional Display

2009 ◽  
Vol 75 (17) ◽  
pp. 5461-5466 ◽  
Author(s):  
Anika C. Jahns ◽  
Bernd H. A. Rehm
Keyword(s):  
Fusion Protein ◽  
Fluorescent Protein ◽  
Ralstonia Eutropha ◽  
Class I ◽  
Functional Protein ◽  
Reporter Protein ◽  
Positive Interaction ◽  
C Terminus ◽  
N Terminus ◽  
Polyhydroxyalkanoate Synthase

ABSTRACT Here, the class I polyhydroxyalkanoate synthase (PhaC) from Ralstonia eutropha was investigated regarding the functionality of its conserved C-terminal region and its ability to tolerate translational fusions to its C terminus. MalE, the maltose binding protein, and green fluorescent protein (GFP) were considered reporter proteins to be translationally fused to the C terminus. Interestingly, PhaC remained active only when a linker was inserted between PhaC and MalE, whereas MalE was not functional. However, the extension of the PhaC N terminus by 458 amino acid residues was required to achieve a functionality of MalE. These data suggested a positive interaction of the extended N terminus with the C terminus. To assess whether a linker and/or N-terminal extension is generally required for a functional C-terminal fusion, GFP was fused to the C terminus of PhaC. Both fusion partners were active without the requirement of a linker and/or N-terminal extension. A further reporter protein, the immunoglobulin G binding ZZ domain of protein A, was translationally fused to the N terminus of the fusion protein PhaC-GFP and resulted in a tripartite fusion protein mediating the production of polyester granules displaying two functional protein domains.

scholarly journals The unique tropism ofMycobacterium lepraeto the nasal epithelial cells can be explained by the mammalian cell entry protein 1A

2018 ◽  
Author(s):  
Viesta Beby Fadlitha ◽  
Fuki Yamamoto ◽  
Irfan Idris ◽  
Haslindah Dahlan ◽  
Naoya Sato ◽  
...  
Keyword(s):  
Amino Acids ◽  
Epithelial Cell ◽  
Epithelial Cells ◽  
Recombinant Proteins ◽  
Cell Entry ◽  
Important Region ◽  
C Terminus ◽  
Protein Encoding ◽  
N Terminus ◽  
Encoding Genes

AbstractLeprosy is a chronic infection where the skin and peripheral nervous system is invaded byMycobacterium leprae. The infection mechanism remains unknown in part because culture methods have not been established yet forM.leprae.Mce1A protein (442 aa) is coded by mce1A (1326 bp) ofM.leprae. The mce1A homolog inMycobacterium tuberculosisis known to be associated withM.tuberculosisepithelial cell entry, and survival and multiplication within macrophages. Studies using recombinant proteins have indicated that mce1A ofM.lepraeis also associated with epithelial cell entry. This study is aimed at identifying particular sequences within mce1A associated withM.lepraeepithelial cell entry.Recombinant proteins having N-terminus and C-terminus truncations of the mce1A region ofM.lepraewere created inEschericia coli.Entry activity of latex beads, coated with these truncated proteins (r-lep37kDa and r-lep27kDa), into HeLa cells was observed by electron microscopy. The entry activity was preserved even when 315 bp (105 aa) and 922 bp (308 aa) was truncated from the N-terminus and C-terminus, respectively. This 316 – 921 bp region was divided into three sub-regions: 316 – 531 bp (InvX), 532 – 753 bp (InvY), and 754 – 921 bp (InvZ). Each sub-region was cloned into an AIDA vector and expressed on the surface ofE.coli.Entry of theseE.coliinto monolayer-cultured HeLa and RPMI2650 cells was observed by electron microscopy. OnlyE.coliharboring the InvX sub-region exhibited cell entry. InvX was further divided into 4 domains, InvXa - InvXd, containing sequences 1 – 24 aa, 25 – 46 aa, 47 – 57 aa, and 58 – 72 aa, respectively.RecombinantE.coli, expressing each of InvXa - InvXd on the surface, were treated with antibodies against these domains, then added to monolayer cultured RPMI cells. The effectiveness of these antibodies in preventing cell entry was studied by colony counting. Entry activity was suppressed by antibodies against InvXa, InvXb, and InvXd. This suggests that these three InvX domains of mce1A are important forM.lepraeinvasion into nasal epithelial cells.Author SummaryMce1A protein is encoded by the mce1A region of mce1 locus ofM.tuberculosisandM.leprae, and is involved in the bacteria’s invasion into epithelial cells. The present study revealed that the active sequence ofM.lepraeinvolved in the invasion into nasal mucosa epithelial cells is present in the 316-531 bp region of mce1A.The most important region of mce1A protein involved in the invasion ofM.tuberculosisinto human epithelial cells is called the InvIII region, which is located between amino acids at position 130 to 152. The InvIII region ofM.tuberculosiscorresponds to InvXb ofM.leprae. The sequences of these regions are identical between amino acids at positions 10 to position 22 as counted from the N terminus, except that amino acids at positions 1 to 3, 5, 8, 9, 13 are different betweenM.lepraeandM.tuberculosis. Suppression test results also indicated that the most important region of mce1A protein ofM.lepraeinvolved in the invasion into human epithelial cells is different from thatM.tuberculosis. WhileM.tuberculosishas 3,959 protein-encoding genes and only 6 pseudogenes,M.lepraehas only 1,604 protein-encoding genes but has 1,116 pseudogenes indicating that inM.leprae, far more proteins are inactivated as compared toM.tuberculosis. The present study also revealed that, as inM.tuberculosis,the mce1A protein is expressed on the surface of bacteria as a native protein. In light of these data, the mce1A protein is considered to be one of the most important proteins involved in the invasion ofM.lepraeinto nasal mucosa epithelial cells.

scholarly journals Cloning, expression, purification and interaction evaluation of 30 amino acids in C terminus of Clostridium perfringens toxin with its receptor Claudin-4

2019 ◽  
Vol 2 (4) ◽  
pp. 47-55
Author(s):  
Quang Kien Huynh ◽  
An Hoang Nguyen ◽  
Quynh Thi Mong Pham ◽  
Hoan Phuoc Khai Nguyen ◽  
Hieu Van Tran
Keyword(s):  
Amino Acids ◽  
Fusion Protein ◽  
Clostridium Perfringens ◽  
Field Effect Transistors ◽  
Oral Vaccine ◽  
Soluble Form ◽  
M Cells ◽  
Gastrointestinal Infections ◽  
E Coli ◽  
C Terminus

Oral vaccine is a strategy being the most interested about treatments of gastrointestinal infections because of many great benefits outweigh conventional injection vaccines. In order to resolve the dispersion of antigens in gastrointestinal surfaces, the immunological tolerance and also be capable to stimulate immune responses effectively, M cells are targeted for antigens delivery. A number of researches reported that 30 amino acids in C terminus of Clostridium perfringens toxin (CPE30) have a high affinity to Claudin-4 receptor presenting on M cells. It is highly indispensable to produce a resource for assessing of CPE30 binding ability so cpe30 gene was cloned into the pET-gfp plasmid by two restriction enzymes BamHI and NdeI on the E. coli DH5α strain. The expression and confirmation of the fusion protein CPE30-GFP which was induced by IPTG in E. coli BL21 (DE3) strain and assessed by SDS-PAGE and Western blot with 6xHis Taq antibody demonstrated that there was the over expression of CPE30 GFP fusion protein in the cytoplasm, mainly in the soluble form. Finally, CPE30-GFP was purified which the purity was approximately 92.3%. In vitro protein interaction measurement using silicon nanowire field-effect transistors (SiNW FETs) showed that CPE30-GFP had a good binding affinity with its receptor Claudin-4 (R4). This result laid the groundwork for the CPE30 interaction study with the M cell in vivo.

scholarly journals Identification of a Novel Self-Sufficient Styrene Monooxygenase from Rhodococcus opacus 1CP

2009 ◽  
Vol 191 (15) ◽  
pp. 4996-5009 ◽  
Author(s):  
Dirk Tischler ◽  
Dirk Eulberg ◽  
Silvia Lakner ◽  
Stefan R. Kaschabek ◽  
Willem J. H. van Berkel ◽  
...  
Keyword(s):  
Amino Acids ◽  
Fusion Protein ◽  
Styrene Oxide ◽  
Functional Expression ◽  
Rhodococcus Opacus ◽  
Reading Frame ◽  
Arthrobacter Aurescens ◽  
C Terminus ◽  
Two Component ◽  
Rhodococcus Opacus 1Cp

ABSTRACT Sequence analysis of a 9-kb genomic fragment of the actinobacterium Rhodococcus opacus 1CP led to identification of an open reading frame encoding a novel fusion protein, StyA2B, with a putative function in styrene metabolism via styrene oxide and phenylacetic acid. Gene cluster analysis indicated that the highly related fusion proteins of Nocardia farcinica IFM10152 and Arthrobacter aurescens TC1 are involved in a similar physiological process. Whereas 413 amino acids of the N terminus of StyA2B are highly similar to those of the oxygenases of two-component styrene monooxygenases (SMOs) from pseudomonads, the residual 160 amino acids of the C terminus show significant homology to the flavin reductases of these systems. Cloning and functional expression of His10-StyA2B revealed for the first time that the fusion protein does in fact catalyze two separate reactions. Strictly NADH-dependent reduction of flavins and highly enantioselective oxygenation of styrene to (S)-styrene oxide were shown. Inhibition studies and photometric analysis of recombinant StyA2B indicated the absence of tightly bound heme and flavin cofactors in this self-sufficient monooxygenase. StyA2B oxygenates a spectrum of aromatic compounds similar to those of two-component SMOs. However, the specific activities of the flavin-reducing and styrene-oxidizing functions of StyA2B are one to two orders of magnitude lower than those of StyA/StyB from Pseudomonas sp. strain VLB120.

scholarly journals Study on Cecropin B2 Production via Construct Bearing Intein Oligopeptide Cleavage Variants

Molecules ◽  
2020 ◽  
Vol 25 (4) ◽  
pp. 1005
Author(s):  
Yi-Ting Fang ◽  
Si-Yu Li ◽  
Nien-Jen Hu ◽  
Jie Yang ◽  
Jyung-Hurng Liu ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Amino Acids ◽  
Fusion Protein ◽  
Md Simulation ◽  
Cleavage Reaction ◽  
Chitin Binding Domain ◽  
First Order ◽  
C Terminus ◽  
Efficient Performance ◽  
Order Rate Equation

In this study, genetic engineering was applied to the overexpression of the antimicrobial peptide (AMP) cecropin B2 (cecB2). pTWIN1 vector with a chitin-binding domain (CBD) and an auto-cleavage Ssp DnaB intein (INT) was coupled to the cecB2 to form a fusion protein construct and expressed via Escherichia coli ER2566. The cecB2 was obtained via the INT cleavage reaction, which was highly related to its adjacent amino acids. Three oligopeptide cleavage variants (OCVs), i.e., GRA, CRA, and SRA, were used as the inserts located at the C-terminus of the INT to facilitate the cleavage reaction. SRA showed the most efficient performance in accelerating the INT self-cleavage reaction. In addition, in order to treat the INT as a biocatalyst, a first-order rate equation was applied to fit the INT cleavage reaction. A possible inference was proposed for the INT cleavage promotion with varied OCVs using a molecular dynamics (MD) simulation. The production and purification via the CBD-INT-SRA-cecB2 fusion protein resulted in a cecB2 yield of 58.7 mg/L with antimicrobial activity.

scholarly journals Construction and Evaluation of a Novel Bifunctional N-Carbamylase–d-Hydantoinase Fusion Enzyme

2000 ◽  
Vol 66 (5) ◽  
pp. 2133-2138 ◽  
Author(s):  
Geun-Joong Kim ◽  
Dong-Eun Lee ◽  
Hak-Sung Kim
Keyword(s):  
Amino Acids ◽  
Fusion Protein ◽  
Bacillus Stearothermophilus ◽  
Gel Filtration ◽  
Intact Protein ◽  
E Coli ◽  
Fusion Enzyme ◽  
N Terminus ◽  
Fusion Enzymes ◽  
Hydantoin Derivatives

ABSTRACT A fully enzymatic process employing two sequential enzymes,d-hydantoinase and N-carbamylase, is a typical case requiring combined enzyme activity for the production ofd-amino acids. To test the possibility of generating a bifunctional fusion enzyme, we constructed a fusion protein via end-to-end fusion of a whole gene that encodes an intact protein at the N terminus of the d-hydantoinase. Firstly, maltose-binding protein (MBP) gene of E. coli was fused withd-hydantoinase gene from Bacillus stearothermophilus SD1, and the properties of the resulting fusion protein (MBP-HYD) were compared with those of natived-hydantoinase. Gel filtration and kinetic analyses clearly demonstrated that the typical characteristics ofd-hydantoinase are maintained even in a fusion state. Based on this result, we constructed an artificial fusion enzyme composed of the whole length of N-carbamylase (304 amino acids [aa]) from Agrobacterim radiobacter NRRL B11291 andd-hydantoinase (471 aa). The fusion enzyme (CAB-HYD) was functionally expressed with an expected molecular mass of 86 kDa and efficiently converted exogenous hydantoin derivatives to thed-amino acids. A related d-hydantoinase (HYD1) gene from Bacillus thermocatenulatus GH2 was also fused with the N-carbamylase gene at its N terminus. The resulting enzyme (CAB-HYD1) was bifunctional as expected and showed better performance than the CAB-HYD fusion enzyme. The conversion of hydantoin derivatives to corresponding amino acids by the fusion enzymes was much higher than that by the separately expressed enzymes, and comparable to that by the coexpressed enzymes. Thus, the fusion enzyme might be useful as a potential biocatalyst for the production of nonnatural amino acids.

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