Noncharged amino acid residues at the solvent-exposed positions in the middle and at the C terminus of the α-helix have the same helical propensity

Biochemical and physiological studies of Synechococcus cyanobacteria have indicated the presence of a low-Mr heavy-metal-binding protein with marked similarity to eukaryotic metallothioneins (MTs). We report here the characterization of a Synechococcus prokaryotic MT isolated by gel-permeation and reverse-phase chromatography. The large number of variants of this molecule found during chromatographic separation could not be attributed to the presence of major isoproteins as assessed by amino acid analysis and amino acid sequencing of isoforms. Two of the latter were shown to have identical primary structures that differed substantially from the well-described eukaryotic MTs. In addition to six long-chain aliphatic residues, two aromatic residues were found adjacent to one another near the centre of the molecule, making this the most hydrophobic MT to be described. Other unusual features included a pair of histidine residues located in repeating Gly-His-Thr-Gly sequences near the C-terminus and a complete lack of association of hydroxylated residues with cysteine residues, as is commonly found in eukaryotes. Similarly, aside from a single lysine residue, no basic amino acid residues were found adjacent to cysteine residues in the sequence. Most importantly, sequence alignment analyses with mammalian, invertebrate and fungal MT sequences showed no statistically significant homology aside from the presence of Cys-Xaa-Cys structures common to all MTs. On the other hand, like other MTs, the prokaryotic molecule appears to be free of alpha-helical structure but has a considerable amount of beta-structure, as predicted by both c.d. measurements and the Chou & Fasman empirical relations. Considered together, these data suggested that some similarity between the metal-thiolate clusters of the prokaryote and eukaryote MTs may exist.

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Deletion of the Actin-Associated Tropomyosin Tpm3 Leads to Reduced Cell Complexity in Cultured Hippocampal Neurons—New Insights into the Role of the C-Terminal Region of Tpm3.1

Cells ◽

10.3390/cells10030715 ◽

2021 ◽

Vol 10 (3) ◽

pp. 715

Author(s):

Tamara Tomanić ◽

Claire Martin ◽

Holly Stefen ◽

Esmeralda Parić ◽

Peter Gunning ◽

...

Keyword(s):

Amino Acid ◽

Hippocampal Neurons ◽

Molecular Mechanisms ◽

Growth Cones ◽

Amino Acid Residues ◽

Terminal Amino Acid ◽

C Terminus ◽

Primary Mouse ◽

Terminal Amino

Tropomyosins (Tpms) have been described as master regulators of actin, with Tpm3 products shown to be involved in early developmental processes, and the Tpm3 isoform Tpm3.1 controlling changes in the size of neuronal growth cones and neurite growth. Here, we used primary mouse hippocampal neurons of C57/Bl6 wild type and Bl6Tpm3flox transgenic mice to carry out morphometric analyses in response to the absence of Tpm3 products, as well as to investigate the effect of C-terminal truncation on the ability of Tpm3.1 to modulate neuronal morphogenesis. We found that the knock-out of Tpm3 leads to decreased neurite length and complexity, and that the deletion of two amino acid residues at the C-terminus of Tpm3.1 leads to more detrimental changes in neurite morphology than the deletion of six amino acid residues. We also found that Tpm3.1 that lacks the 6 C-terminal amino acid residues does not associate with stress fibres, does not segregate to the tips of neurites, and does not impact the amount of the filamentous actin pool at the axonal growth cones, as opposed to Tpm3.1, which lacks the two C-terminal amino acid residues. Our study provides further insight into the role of both Tpm3 products and the C-terminus of Tpm3.1, and it forms the basis for future studies that aim to identify the molecular mechanisms underlying Tpm3.1 targeting to different subcellular compartments.

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An Extended α-Helix and Specific Amino Acid Residues Opposite the DNA-binding Surface of the cAMP Response Element Binding Protein Basic Domain Are Important for Human T Cell Lymphotropic Retrovirus Type I Tax Binding

Journal of Biological Chemistry ◽

10.1074/jbc.273.42.27339 ◽

1998 ◽

Vol 273 (42) ◽

pp. 27339-27346 ◽

Cited By ~ 15

Author(s):

Yong Tang ◽

Feng Tie ◽

Imre Boros ◽

Robert Harrod ◽

Mark Glover ◽

...

Keyword(s):

Amino Acid ◽

Camp Response Element Binding ◽

Type I ◽

Amino Acid Residues ◽

Camp Response Element ◽

Specific Amino Acid ◽

Human T Cell ◽

Binding Surface ◽

Element Binding Protein ◽

Α Helix

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Peroxisome targeting signal of rat liver acyl-coenzyme A oxidase resides at the carboxy terminus

Molecular and Cellular Biology ◽

10.1128/mcb.9.1.83-91.1989 ◽

1989 ◽

Vol 9 (1) ◽

pp. 83-91

Author(s):

S Miyazawa ◽

T Osumi ◽

T Hashimoto ◽

K Ohno ◽

S Miura ◽

...

Keyword(s):

Amino Acid ◽

Rat Liver ◽

Coenzyme A ◽

Terminal Region ◽

Proteinase K ◽

Amino Acid Residues ◽

C Terminus ◽

Targeting Signal ◽

Acyl Coenzyme A

To identify the topogenic signal of peroxisomal acyl-coenzyme A oxidase (AOX) of rat liver, we carried out in vitro import experiments with mutant polypeptides of the enzyme. Full-length AOX and polypeptides that were truncated at the N-terminal region were efficiently imported into peroxisomes, as determined by resistance to externally added proteinase K. Polypeptides carrying internal deletions in the C-terminal region exhibited much lower import activities. Polypeptides that were truncated or mutated at the extreme C terminus were totally import negative. When the five amino acid residues at the extreme C terminus were attached to some of the import-negative polypeptides, the import activities were rescued. Moreover, the C-terminal 199 and 70 amino acid residues of AOX directed fusion proteins with two bacterial enzymes to peroxisomes. These results are interpreted to mean that the peroxisome targeting signal of AOX residues at the C terminus and the five or fewer residues at the extreme terminus have an obligatory function in targeting. The C-terminal internal region also has an important role for efficient import, possibly through a conformational effect.

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Modèle topologique de la structure d’un antiport vacuolaire de type NHX chez la vigne cultivée (Vitis vinifera)

Botany ◽

10.1139/b08-141 ◽

2009 ◽

Vol 87 (3) ◽

pp. 339-347 ◽

Cited By ~ 1

Author(s):

Mohsen Hanana ◽

Olivier Cagnac ◽

Ahmed Mliki ◽

Eduardo Blumwald

Keyword(s):

Amino Acid ◽

Vitis Vinifera ◽

Molecular Mass ◽

Electrostatic Interactions ◽

Functional Characterization ◽

Terminal Region ◽

Vitis Vinifera L ◽

Amino Acid Residues ◽

Transmembrane Segments ◽

Α Helix

After identifying and isolating a grapevine ( Vitis vinifera L.) NHX vacuolar antiporter and before initializing functional genomic studies, we juged necessary to acquire a minimum of knowledge about the VvNHX1 protein. Thus, we realized a bioinformatic analysis to determine its basic characteristics and to get structural informations that could guide us through the functional characterization. We have determined important physico-chemical parameters (molecular mass, isoelectric point, hydrophobic regions, etc.) and obtained interesting structural data (primary, secondary, and tertiary structures; conserved domains and interaction motives; etc.). The VvNHX1 gene, which encodes this 541 amino-acid protein with a predicted molecular mass of 60 kDa, is made of 14 exons and measures 6.5 kb. The amino-acidic composition of this protein is very important, in particular, for the establishment of the α-helix structure, which represents more than 50% of the protein, but also for charge distribution, which generates critical electrostatic interactions for the ionic flux. The secondary structure of VvNHX1 contains multiple transmembrane α-helix segments that are made of hydrophobic amino-acid residues, thus facilitating its insertion in the membrane. Globally, VvNHX1 has one hydrophobic N-terminal region, made of 10 transmembrane segments with 440 amino-acid residues, and one hydrophilic C-terminal region, made of 100 residues. The region located between the fourth and fifth transmembrane segments represents, with its structure mainly helicoidal and the presence of a favourable electrostatic environment, the pore where cation flux is performed across the membrane. VvNHX1 contains various interaction domains as well as several putative posttranslational modification sites, mainly at the C-terminus but also at the N-terminus, that play an important part in regulating protein activities, influence protein structural stability, or interact with other proteins or signalling molecules.

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Differentiation of propeptide residues regulating the compartmentalization, maturation and activity of the broad-range phospholipase C of Listeria monocytogenes

Biochemical Journal ◽

10.1042/bj20100557 ◽

2010 ◽

Vol 432 (3) ◽

pp. 557-566 ◽

Cited By ~ 10

Author(s):

Emily R. Slepkov ◽

Alan Pavinski Bitar ◽

Hélène Marquis

Keyword(s):

Cell Wall ◽

Listeria Monocytogenes ◽

Amino Acid ◽

Enzymatic Activity ◽

Phospholipase C ◽

Bacterial Pathogen ◽

Amino Acid Residues ◽

C Terminus ◽

N Terminus ◽

Vacuolar Acidification

The intracellular bacterial pathogen Listeria monocytogenes secretes a broad-range phospholipase C enzyme called PC-PLC (phosphatidylcholine phospholipase C) whose compartmentalization and enzymatic activity is regulated by a 24-amino-acid propeptide (Cys28–Ser51). During intracytosolic multiplication, bacteria accumulate the proform of PC-PLC at their membrane–cell-wall interface, whereas during cell-to-cell spread vacuolar acidification leads to maturation and rapid translocation of PC-PLC across the cell wall in a manner that is dependent on Mpl, the metalloprotease of Listeria. In the present study, we generated a series of propeptide mutants to determine the minimal requirement to prevent PC-PLC enzymatic activity and to identify residues regulating compartmentalization and maturation. We found that a single residue at position P1 (Ser51) of the cleavage site is sufficient to prevent enzymatic activity, which is consistent with P1′ (Trp52) being located within the active-site pocket. We observed that mutants with deletions at the N-terminus, but not the C-terminus, of the propeptide are translocated across the cell wall more effectively than wild-type PC-PLC at a physiological pH, and that individual amino acid residues within the N-terminus influence Mpl-mediated maturation of PC-PLC at acidic pH. However, deletion of more than 75% of the propeptide was required to completely prevent Mpl-mediated maturation of PC-PLC. These results indicate that the N-terminus of the propeptide regulates PC-PLC compartmentalization and that specific residues within the N-terminus influence the ability of Mpl to mediate PC-PLC maturation, although a six-residue propeptide is sufficient for Mpl to mediate PC-PLC maturation.

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The last five amino acid residues at the C-terminus of PRK1/PKN is essential for full lipid responsiveness

Cellular Signalling ◽

10.1016/j.cellsig.2004.12.003 ◽

2005 ◽

Vol 17 (9) ◽

pp. 1084-1097 ◽

Cited By ~ 9

Author(s):

W LIM ◽

Y ZHU ◽

C WANG ◽

B TAN ◽

J ARMSTRONG ◽

...

Keyword(s):

Amino Acid ◽

Amino Acid Residues ◽

C Terminus

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The conserved basic residues and the charged amino acid residues at the α-helix of the zinc finger motif regulate the nuclear transport activity of triple C2H2 zinc finger proteins

PLoS ONE ◽

10.1371/journal.pone.0191971 ◽

2018 ◽

Vol 13 (1) ◽

pp. e0191971 ◽

Cited By ~ 1

Author(s):

Chih-Ying Lin ◽

Lih-Yuan Lin

Keyword(s):

Amino Acid ◽

Zinc Finger ◽

Nuclear Transport ◽

Zinc Finger Proteins ◽

Zinc Finger Motif ◽

Amino Acid Residues ◽

Transport Activity ◽

C2h2 Zinc Finger ◽

Α Helix

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The Respiratory Syncytial Virus M2-1 Protein Forms Tetramers and Interacts with RNA and P in a Competitive Manner

Journal of Virology ◽

10.1128/jvi.00335-09 ◽

2009 ◽

Vol 83 (13) ◽

pp. 6363-6374 ◽

Cited By ~ 52

Author(s):

Thi-Lan Tran ◽

Nathalie Castagné ◽

Virginie Dubosclard ◽

Sylvie Noinville ◽

Emmanuelle Koch ◽

...

Keyword(s):

Respiratory Syncytial Virus ◽

Amino Acid ◽

Rna Binding ◽

Amino Acid Residues ◽

Polymerase Complex ◽

Bacterial Rna ◽

Infected Cells ◽

Syncytial Virus ◽

Α Helix ◽

Zinc Binding Domain

ABSTRACT The respiratory syncytial virus (RSV) M2-1 protein is an essential cofactor of the viral RNA polymerase complex and functions as a transcriptional processivity and antitermination factor. M2-1, which exists in a phosphorylated or unphosphorylated form in infected cells, is an RNA-binding protein that also interacts with some of the other components of the viral polymerase complex. It contains a CCCH motif, a putative zinc-binding domain that is essential for M2-1 function, at the N terminus. To gain insight into its structural organization, M2-1 was produced as a recombinant protein in Escherichia coli and purified to >95% homogeneity by using a glutathione S-transferase (GST) tag. The GST-M2-1 fusion proteins were copurified with bacterial RNA, which could be eliminated by a high-salt wash. Circular dichroism analysis showed that M2-1 is largely α-helical. Chemical cross-linking, dynamic light scattering, sedimentation velocity, and electron microscopy analyses led to the conclusion that M2-1 forms a 5.4S tetramer of 89 kDa and ∼7.6 nm in diameter at micromolar concentrations. By using a series of deletion mutants, the oligomerization domain of M2-1 was mapped to a putative α-helix consisting of amino acid residues 32 to 63. When tested in an RSV minigenome replicon system using a luciferase gene as a reporter, an M2-1 deletion mutant lacking this region showed a significant reduction in RNA transcription compared to wild-type M2-1, indicating that M2-1 oligomerization is essential for the activity of the protein. We also show that the region encompassing amino acid residues 59 to 178 binds to P and RNA in a competitive manner that is independent of the phosphorylation status of M2-1.

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The Acinetobacter baylyi hfq Gene Encodes a Large Protein with an Unusual C Terminus

Journal of Bacteriology ◽

10.1128/jb.00490-09 ◽

2009 ◽

Vol 191 (17) ◽

pp. 5553-5562 ◽

Cited By ~ 20

Author(s):

Dominik Schilling ◽

Ulrike Gerischer

Keyword(s):

Amino Acid ◽

Gene Localization ◽

Amino Acid Residues ◽

Acinetobacter Baylyi ◽

Reading Frame ◽

Rich Domain ◽

C Terminus ◽

The Difference ◽

Cell Phenotypes

ABSTRACT In gammaproteobacteria the Hfq protein shows a great variation in size, especially in its C-terminal part. Extremely large Hfq proteins consisting of almost 200 amino acid residues and more are found within the gammaproteobacterial family Moraxellaceae. The difference in size compared to other Hfq proteins is due to a glycine-rich domain near the C-terminal end of the protein. Acinetobacter baylyi, a nonpathogenic soil bacterium and member of the Moraxellaceae encodes a large 174-amino-acid Hfq homologue containing the unique and repetitive amino acid pattern GGGFGGQ within the glycine-rich domain. Despite the presence of the C-terminal extension, A. baylyi Hfq complemented an Escherichia coli hfq mutant in vivo. By using polyclonal anti-Hfq antibodies, we detected the large A. baylyi Hfq that corresponds to its annotated size indicating the expression and stability of the full protein. Deletion of the complete A. baylyi hfq open reading frame resulted in severe reduction of growth. In addition, a deletion or overexpression of Hfq was accompanied by the loss of cell chain assembly. The glycine-rich domain was not responsible for growth and cell phenotypes. hfq gene localization in A. baylyi is strictly conserved within the mutL-miaA-hfq operon, and we show that hfq expression starts within the preceding miaA gene or further upstream.

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