scholarly journals Activity of the Mason-Pfizer Monkey Virus Fusion Protein Is Modulated by Single Amino Acids in the Cytoplasmic Tail

2005 ◽  
Vol 79 (18) ◽  
pp. 11569-11579 ◽  
Author(s):  
Chisu Song ◽  
Keith Micoli ◽  
Eric Hunter
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Coiled Coil ◽  
Cytoplasmic Tail ◽  
Amino Acid Residues ◽  
Protein Fusion ◽  
Glycoprotein Complex ◽  
Transmembrane Glycoprotein ◽  
Immature Virus

ABSTRACT Mason-Pfizer monkey virus (M-PMV) encodes a transmembrane glycoprotein with a 38-amino-acid-long cytoplasmic tail. After the release of the immature virus, a viral protease-mediated cleavage of the cytoplasmic tail (CT) results in the loss of 17 amino acids from the carboxy terminus and renders the envelope protein fusion competent. To investigate the role of individual amino acid residues in the CT in fusion, a series of mutations was introduced, and the effects of these mutations on glycoprotein biosynthesis and fusion were examined. Most of the alanine-scanning mutations in the CT had little effect on fusion activity. However, four amino acid substitutions (threonine 4, lysine 7, glutamine 9, and isoleucine 10) resulted in substantially increased fusogenicity, while six (leucine 2, phenylalanine 5, isoleucine 13, lysine 16, proline 17, and glycine 31) resulted in much-reduced fusion. Interestingly, the bulk of these mutations are located upstream of the CT cleavage site in a region that has the potential to form a coiled-coil in the Env trimer. Substitutions at glutamine 9 and isoleucine 10 with alanine had the most dramatic positive effect and resulted in the formation of large syncytia. Taken together, these data demonstrate that individual residues within the cytoplasmic domain of M-PMV Env can modulate, in both a positive and negative manner, biological functions that are associated with the extracellular domains of the glycoprotein complex.

scholarly journals A Novel Cytoplasmic Tail MXXXL Motif Mediates the Internalization of Prostate-specific Membrane Antigen

2003 ◽  
Vol 14 (12) ◽  
pp. 4835-4845 ◽  
Author(s):  
Sigrid A. Rajasekaran ◽  
Gopalakrishnapillai Anilkumar ◽  
Eri Oshima ◽  
James U. Bowie ◽  
He Liu ◽  
...  
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Transmembrane Protein ◽  
Interleukin 2 ◽  
Adaptor Protein ◽  
Cytoplasmic Tail ◽  
Prostate Specific Membrane Antigen ◽  
Amino Acid Residues ◽  
Terminal Amino ◽  
Specific Membrane

Prostate-specific membrane antigen (PSMA) is a transmembrane protein expressed at high levels in prostate cancer and in tumor-associated neovasculature. In this study, we report that PSMA is internalized via a clathrin-dependent endocytic mechanism and that internalization of PSMA is mediated by the five N-terminal amino acids (MWNLL) present in its cytoplasmic tail. Deletion of the cytoplasmic tail abolished PSMA internalization. Mutagenesis of N-terminal amino acid residues at position 2, 3, or 4 to alanine did not affect internalization of PSMA, whereas mutation of amino acid residues 1 or 5 to alanine strongly inhibited internalization. Using a chimeric protein composed of Tac antigen, the α-chain of interleukin 2-receptor, fused to the first five amino acids of PSMA (Tac-MWNLL), we found that this sequence is sufficient for PSMA internalization. In addition, inclusion of additional alanines into the MWNLL sequence either in the Tac chimera or the full-length PSMA strongly inhibited internalization. From these results, we suggest that a novel MXXXL motif in the cytoplasmic tail mediates PSMA internalization. We also show that dominant negative μ2 of the adaptor protein (AP)-2 complex strongly inhibits the internalization of PSMA, indicating that AP-2 is involved in the internalization of PSMA mediated by the MXXXL motif.

scholarly journals Role of Transmembrane Domain and Cytoplasmic Tail Amino Acid Sequences of Influenza A Virus Neuraminidase in Raft Association and Virus Budding

2004 ◽  
Vol 78 (10) ◽  
pp. 5258-5269 ◽  
Author(s):  
Subrata Barman ◽  
Lopa Adhikary ◽  
Alok K. Chakrabarti ◽  
Carl Bernas ◽  
Yoshihiro Kawaoka ◽  
...  
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Influenza A ◽  
Transmembrane Domain ◽  
Amino Acid Sequences ◽  
Type Ii ◽  
Virus Growth ◽  
Transmembrane Glycoprotein ◽  
Virus Life Cycle

ABSTRACT Influenza virus neuraminidase (NA), a type II transmembrane glycoprotein, possesses receptor-destroying activity and thereby facilitates virus release from the cell surface. Among the influenza A viruses, both the cytoplasmic tail (CT) and transmembrane domain (TMD) amino acid sequences of NA are highly conserved, yet their function(s) in virus biology remains unknown. To investigate the role of amino acid sequences of the CT and TMD on the virus life cycle, we systematically mutagenized the entire CT and TMD of NA by converting two to five contiguous amino acids to alanine. In addition, we also made two chimeric NA by replacing the CT proximal one-third amino acids of the NA TMD [NA(1T2N)NA] and the entire NA TMD (NATRNA) with that of human transferrin receptor (TR) (a type II transmembrane glycoprotein). We rescued transfectant mutant viruses by reverse genetics and examined their phenotypes. Our results show that all mutated and chimeric NAs could be rescued into transfectant viruses. Different mutants showed pleiotropic effects on virus growth and replication. Some mutants (NA2A5, NA3A7, and NA4A10) had little effect on virus growth while others (NA3A2, NA5A27, and NA5A31) produced about 50- to 100-fold-less infectious virus and still some others (NA5A14, NA4A19, and NA4A23) exhibited an intermediate phenotype. In general, mutations towards the ectodomain-proximal sequences of TMD progressively caused reduction in NA enzyme activity, affected lipid raft association, and attenuated virus growth. Electron microscopic analysis showed that these mutant viruses remained aggregated and bound to infected cell surfaces and could be released from the infected cells by bacterial NA treatment. Moreover, viruses containing mutations in the extreme N terminus of the CT (NA3A2) as well as chimeric NA containing the TMD replaced partially [NA(1T2N)NA] or fully (NATRNA) with TR TMD caused reduction in virus growth and exhibited the morphological phenotype of elongated particles. These results show that although the sequences of NA CT and TMD per se are not absolutely essential for the virus life cycle, specific amino acid sequences play a critical role in providing structural stability, enzyme activity, and lipid raft association of NA. In addition, aberrant morphogenesis including elongated particle formation of some mutant viruses indicates the involvement of NA in virus morphogenesis and budding.

The role of hydrophobic, aromatic and electrostatic interactions between amino acid residues and a titanium dioxide surface

2018 ◽  
Vol 20 (47) ◽  
pp. 29811-29816 ◽  
Author(s):  
Avia Leader ◽  
Daniel Mandler ◽  
Meital Reches
Keyword(s):  
Amino Acids ◽  
Titanium Dioxide ◽  
Amino Acid ◽  
Electrostatic Interactions ◽  
Amino Acid Residues ◽  
New Materials ◽  
Titanium Dioxide Surface

Understanding the nature of interactions between inorganic surfaces and biomolecules, such as amino acids and peptides, can enhance the development of new materials.

scholarly journals Cohesin-Dockerin Interactions of Cellulosomal Subunits of Clostridium cellulovorans

2001 ◽  
Vol 183 (18) ◽  
pp. 5431-5435 ◽  
Author(s):  
Jae-Seon Park ◽  
Yutaka Matano ◽  
Roy H. Doi
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Fusion Proteins ◽  
Sequence Similarity ◽  
Binding Specificity ◽  
Scaffolding Protein ◽  
Amino Acid Residues ◽  
Clostridium Cellulovorans ◽  
Level Sequence

ABSTRACT The cellulosome of Clostridium cellulovorans consists of three major subunits: CbpA, EngE, and ExgS. The C. cellulovorans scaffolding protein (CbpA) contains nine hydrophobic repeated domains (cohesins) for the binding of enzymatic subunits. Cohesin domains are quite homologous, but there are some questions regarding their binding specificity because some of the domains have regions of low-level sequence similarity. Two cohesins which exhibit 60% sequence similarity were investigated for their ability to bind cellulosomal enzymes. Cohesin 1 (Coh1) was found to contain amino acid residues corresponding to amino acids 312 to 453 of CbpA, which contains a total of 1,848 amino acid residues. Coh6 was determined to contain amino acid residues corresponding to residues 1113 to 1254 of CbpA. By genetic construction, these two cohesins were each fused to MalE, producing MalE-Coh1 and MalE-Coh6. The abilities of two fusion proteins to bind to EngE, ExgS, and CbpA were compared. Although MalE-Coh6 could bind EngE and ExgS, little or no binding of the enzymatic subunits was observed with MalE-Coh1. Significantly, the abilities of the two fusion proteins to bind CbpA were similar. The binding of dockerin-containing enzymes to cohesin-containing proteins was suggested as a model for assembly of cellulosomes. In our examination of the role of dockerins, it was also shown that the binding of endoglucanase B (EngB) to CbpA was dependent on the presence of EngB's dockerin. These results suggest that different cohesins may function with differing efficiency and specificity, that cohesins may play some role in the formation of polycellulosomes through Coh-CbpA interactions, and that dockerins play an important role during the interaction of cellulosomal enzymes and cohesins present in CbpA.

scholarly journals Assembly and routing of von Willebrand factor variants: the requirements for disulfide-linked dimerization reside within the carboxy-terminal 151 amino acids.

1991 ◽  
Vol 113 (1) ◽  
pp. 195-205 ◽  
Author(s):  
J Voorberg ◽  
R Fontijn ◽  
J Calafat ◽  
H Janssen ◽  
J A van Mourik ◽  
...  
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Von Willebrand Factor ◽  
Amino Acid Residues ◽  
Mutant Proteins ◽  
Carboxy Terminal Region ◽  
Carboxy Terminal ◽  
Von Willebrand ◽  
Willebrand Factor

The precursor protein of von Willebrand factor (pro-vWF) consists of four different repeated domains, denoted D1-D2-D'-D3-A1-A2-A3-D4-B1-B2-B3-C1-C2, followed by a carboxy-terminal region of 151 amino acids without obvious internal homology. Previously, we have shown the requirement of the domains D1, D2, D', and D3 of pro-vWF in the assembly of pro-vWF dimers into multimers. Here, we define the domains of vWF involved in dimerization, using deletion mutants of full-length vWF cDNA transiently expressed in monkey kidney COS-1 cells. It is shown that only the carboxy-terminal 151 amino acid residues of vWF are required for dimerization. In addition, by analyzing a construct, encoding only the carboxy-terminal 151 amino acids of vWF, we find that the formation of dimers is an event independent of other domains present on pro-vWF, such as the domains C1 and C2 previously suggested to be involved in dimerization. Furthermore, it is shown that a deletion mutant of vWF, lacking the carboxy-terminal 151 amino acid residues and thus unable to dimerize, is proteolytically degraded in the ER. In contrast, a mutant protein, composed only of the carboxy-terminal 151 amino acids of vWF, and able to dimerize, is transported from the ER in a similar fashion as wild-type vWF. The role of the ER in the assembly of vWF is discussed with regard to the data presented in this paper on the intracellular fate of several vWF mutant proteins.

scholarly journals The Cytoplasmic Tail of α1,2-Fucosyltransferase Contains a Sequence for Golgi Localization

2001 ◽  
Vol 276 (15) ◽  
pp. 12012-12018 ◽  
Author(s):  
Julie Milland ◽  
Simon G. Taylor ◽  
Hayley C. Dodson ◽  
Ian F. C. McKenzie ◽  
Mauro S. Sandrin
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Cytoplasmic Tail ◽  
Single Amino Acid ◽  
Predominant Role ◽  
Golgi Localization ◽  
Sequential Addition ◽  
Golgi Network ◽  
Flanking Regions

The Golgi apparatus has a central role in the glycosylation of proteins and lipids. There is a sequential addition of carbohydrates by glycosyltransferases that are distributed within the Golgi in the order in which the glycosylation occurs. The mechanism of glycosyltransferase retention is considered to involve their transmembrane domains and flanking regions, although we have shown that the cytoplasmic tail of α1,2-fucosyltransferase is important for its Golgi localization. Here we show that the removal of the α1,2-fucosyltransferase cytoplasmic tail altered its function of fucosylation and its localization site. When the tail was removed, the enzyme moved from the Golgi to the trans Golgi network, suggesting that the transmembrane is responsible for retention and that the cytoplasmic tail is responsible for localization. The cytoplasmic tail of α1,2-fucosyltransferase contains 8 amino acids (MWVPSRRH), and mutating these to alanine indicated a role for amino acids 3 to 7 in localization with a particular role of Ser5. Mutagenesis of Ser5to amino acids containing an hydroxyl (Tyr and Thr) demonstrated that the hydroxyl at position 5 is important. Thus, the cytoplasmic tail, and especially a single amino acid, has a predominant role in the localization and thus the function of α1,2-fucosyltransferase.

scholarly journals Role of Conserved Amino Acids in the Catalytic Activity of Escherichia coli Primase

2006 ◽  
Vol 188 (10) ◽  
pp. 3614-3621 ◽  
Author(s):  
Anna Rodina ◽  
G. Nigel Godson
Keyword(s):  
Escherichia Coli ◽  
Amino Acids ◽  
Catalytic Activity ◽  
Amino Acid ◽  
De Novo ◽  
Amino Acid Residues ◽  
Significant Step ◽  
Intermediate Size ◽  
Conserved Amino Acids

ABSTRACT The role of conserved amino acid residues in the polymerase domain of Escherichia coli primase has been studied by mutagenesis. We demonstrate that each of the conserved amino acids Arg146, Arg221, Tyr230, Gly266, and Asp311 is involved in the process of catalysis. Residues Glu265 and Asp309 are also critical because a substitution of each amino acid irreversibly destroys the catalytic activity. Two K229A and M268A mutant primase proteins synthesize only 2-nucleotide products in de novo synthesis reactions under standard conditions. Y267A mutant primase protein synthesizes both full-size and 2-nucleotide RNA, but with no intermediate-size products. From these data we discuss the significant step of the 2-nucleotide primer RNA synthesis by E. coli primase and the role of amino acids Lys229, Tyr267, and Met268 in primase complex stability.

scholarly journals Thiazole–amino acids: influence of thiazole ring on conformational properties of amino acid residues

Amino Acids ◽  
2021 ◽  
Author(s):  
Monika Staś ◽  
Małgorzata A. Broda ◽  
Dawid Siodłak
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Dft Method ◽  
Structural Motif ◽  
Thiazole Ring ◽  
Amino Acid Residues ◽  
Conformational Preferences ◽  
Macrocyclic Peptides ◽  
Structural Database

Abstract Post-translational modified thiazole–amino acid (Xaa–Tzl) residues have been found in macrocyclic peptides (e.g., thiopeptides and cyanobactins), which mostly inhibit protein synthesis in Gram + bacteria. Conformational study of the series of model compounds containing this structural motif with alanine, dehydroalanine, dehydrobutyrine and dehydrophenylalanine were performed using DFT method in various environments. The solid-state crystal structure conformations of thiazole–amino acid residues retrieved from the Cambridge Structural Database were also analysed. The studied structural units tend to adopt the unique semi-extended β2 conformation; which is stabilised mainly by N–H⋯NTzl hydrogen bond, and for dehydroamino acids also by π-electron conjugation. The conformational preferences of amino acids with a thiazole ring were compared with oxazole analogues and the role of the sulfur atom in stabilising the conformations of studied peptides was discussed.

10 THE ROLE OF DIETARY L-SERINE IN THE REGULATION OF INTESTINAL MUCUS BARRIER DURING INFLAMMATION

2020 ◽  
Vol 26 (Supplement_1) ◽  
pp. S42-S42
Author(s):  
Kohei Sugihara ◽  
Nobuhiko Kamada
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Gut Microbiota ◽  
Control Diet ◽  
Bacterial Strains ◽  
Germ Free ◽  
Intestinal Mucus ◽  
Gnotobiotic Mice ◽  
Mucus Barrier

Abstract Background Recent accumulating evidence suggests that amino acids have crucial roles in the maintenance of intestinal homeostasis. In inflammatory bowel disease (IBD), amino acid metabolism is changed in both host and the gut microbiota. Among amino acids, L-serine plays a central role in several metabolic processes that are essential for the growth and survival of both mammalian and bacterial cells. However, the role of L-serine in intestinal homeostasis and IBD remains incompletely understood. In this study, we investigated the effect of dietary L-serine on intestinal inflammation in a murine model of colitis. Methods Specific pathogen-free (SPF) mice were fed either a control diet (amino acid-based diet) or an L-serine-deficient diet (SDD). Colitis was induced by the treatment of dextran sodium sulfate (DSS). The gut microbiome was analyzed by 16S rRNA sequencing. We also evaluate the effect of dietary L-serine in germ-free mice and gnotobiotic mice that were colonized by a consortium of non-mucolytic bacterial strains or the consortium plus mucolytic bacterial strains. Results We found that the SDD exacerbated experimental colitis in SPF mice. However, the severity of colitis in SDD-fed mice was comparable to control diet-fed mice in germ-free condition, suggesting that the gut microbiota is required for exacerbation of colitis caused by the restriction of dietary L-serine. The gut microbiome analysis revealed that dietary L-serine restriction fosters the blooms of a mucus-degrading bacterium Akkermansia muciniphila and adherent-invasive Escherichia coli in the inflamed gut. Consistent with the expansion of mucolytic bacteria, SDD-fed mice showed a loss of the intestinal mucus layer. Dysfunction of the mucus barrier resulted in increased intestinal permeability, thereby leading to bacterial translocation to the intestinal mucosa, which subsequently increased the severity of colitis. The increased intestinal permeability and subsequent bacterial translocation were observed in SDD-fed gnotobiotic mice that colonized by mucolytic bacteria. In contrast, dietary L-serine restriction did not alter intestinal barrier integrity in gnotobiotic mice that colonized only by non-mucolytic bacteria. Conclusion Our results suggest that dietary L-serine regulates the integrity of the intestinal mucus barrier during inflammation by limiting the expansion of mucus degrading bacteria.

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