scholarly journals The N-terminal amino acid sequence of pig kidney endopeptidase-24.11 shows homology with pro-sucrase-isomaltase

1986 ◽  
Vol 240 (1) ◽  
pp. 305-308 ◽  
Author(s):  
I S Fulcher ◽  
D J Pappin ◽  
A J Kenny

Endopeptidase-24.11 (EC 3.4.24.11), a widely distributed ectoenzyme, was isolated from pig kidneys by detergent solubilization of membranes and immuno-affinity chromatography. In all, 12 preparations of the enzyme were submitted to solid-phase sequencing, yielding a consensus sequence of 25 amino acid residues of the N-terminal segment. Some samples were treated with either trypsin or Staphylococcus aureus V8 proteinase before sequencing. There were four lysine and one arginine residues in the first nine positions. This segment was susceptible to hydrolysis by trypsin and, in some samples, to endogenous proteinases. From residue 19 onwards, the sequence became intensely hydrophobic. There was a striking homology with the N-terminal sequence of pro-sucrase-isomaltase. From Lys7 to Leu20 there were seven identical amino acid residues and four conservative substitutions. We suggest that endopeptidase-24.11 is topologically similar to this glycosidase, the N-terminus at the cytoplasmic face and hydrophobic segment serving the roles of both signal peptide and hydrophobic anchor.

1975 ◽  
Vol 149 (3) ◽  
pp. 725-732 ◽  
Author(s):  
D G Redman

1. Three very similar proteins, each of approx. 120 amino acid residues but lacking phenylalanine and histidine, were isolated from wheat (Triticum aestivum) flour in sufficient quantities for further structural studies. 2. Each protein, after reduction and carboxymethylation, was cleaved at the three methionine residues with CNBr to give four major peptides, which were isolated. These peptides are suitable for future sequencing studies, as the sums of their amino acid compositions are in good agreement with those of the whole proteins. 3. The N- and C-terminal peptides were identified. 4. Evidence from amino acid analyses, N-terminal amino acids and electrophoretic mobilities of the peptides suggests a high degree of homology between the proteins. Definite differences in C-terminal amino acids and the number of glycine, alanine and arginine residues were found in the C-terminal peptides.


2002 ◽  
Vol 277 (51) ◽  
pp. 49366-49373 ◽  
Author(s):  
Ke Dong ◽  
LieQi Tang ◽  
Gordon G. MacGregor ◽  
Steven C. Hebert

Intracellular ATP and membrane-associated phosphatidylinositol phospholipids, like PIP2(PI(4,5)P2), regulate the activity of ATP-sensitive K+(KATP) and Kir1.1 channels by direct interaction with the pore-forming subunits of these channels. We previously demonstrated direct binding of TNP-ATP (2′,3′-O-(2,4,6-trinitrophenylcyclo-hexadienylidene)-ATP) to the COOH-terminal cytosolic domains of the pore-forming subunits of Kir1.1 and Kir6.x channels. In addition, PIP2competed for TNP-ATP binding on the COOH termini of Kir1.1 and Kir6.x channels, providing a mechanism that can account for PIP2antagonism of ATP inhibition of these channels. To localize the ATP-binding site within the COOH terminus of Kir1.1, we produced and purified maltose-binding protein (MBP) fusion proteins containing truncated and/or mutated Kir1.1 COOH termini and examined the binding of TNP-ATP and competition by PIP2. A truncated COOH-terminal fusion protein construct, MBP_1.1CΔC170, containing the first 39 amino acid residues distal to the second transmembrane domain was sufficient to bind TNP-ATP with high affinity. A construct containing the remaining COOH-terminal segment distal to the first 39 amino acid residues did not bind TNP-ATP. Deletion of 5 or more amino acid residues from the NH2-terminal side of the COOH terminus abolished nucleotide binding to the entire COOH terminus or to the first 49 amino acid residues of the COOH terminus. PIP2competed TNP-ATP binding to MBP_1.1CΔC170 with an EC50of 10.9 μm. Mutation of any one of three arginine residues (R188A/E, R203A, and R217A), which are conserved in Kir1.1 and KATPchannels and are involved in ATP and/or PIP2effects on channel activity, dramatically reduced TNP-ATP binding to MBP_1.1ΔC170. In contrast, mutation of a fourth conserved residue (R212A) exhibited slightly enhanced TNP-ATP binding and increased affinity for PIP2competition of TNP-ATP (EC50= 5.7 μm). These studies suggest that the first 39 COOH-terminal amino acid residues form an ATP-PIP2binding domain in Kir1.1 and possibly the Kir6.x ATP-sensitive K+channels.


1987 ◽  
Vol 52 (9) ◽  
pp. 2317-2325 ◽  
Author(s):  
Jan Hlaváček ◽  
Jan Pospíšek ◽  
Jiřina Slaninová ◽  
Walter Y. Chan ◽  
Victor J. Hruby

[8-Neopentylglycine]oxytocin (II) and [8-cycloleucine]oxytocin (III) were prepared by a combination of solid-phase synthesis and fragment condensation. Both analogues exhibited decreased uterotonic potency in vitro, each being about 15-30% that of oxytocin. Analogue II also displayed similarly decreased uterotonic potency in vivo and galactogogic potency. On the other hand, analogue III exhibited almost the same potency as oxytocin in the uterotonic assay in vivo and in the galactogogic assay.


1993 ◽  
Vol 13 (4) ◽  
pp. 2554-2563 ◽  
Author(s):  
D Wojciechowicz ◽  
C F Lu ◽  
J Kurjan ◽  
P N Lipke

alpha-Agglutinin is a cell adhesion glycoprotein expressed on the cell wall of Saccharomyces cerevisiae alpha cells. Binding of alpha-agglutinin to its ligand a-agglutinin, expressed by a cells, mediates cell-cell contact during mating. Analysis of truncations of the 650-amino-acid alpha-agglutinin structural gene AG alpha 1 delineated functional domains of alpha-agglutinin. Removal of the C-terminal hydrophobic sequence allowed efficient secretion of the protein and loss of cell surface attachment. This cell surface anchorage domain was necessary for linkage to a glycosyl phosphatidylinositol anchor. A construct expressing the N-terminal 350 amino acid residues retained full a-agglutinin-binding activity, localizing the binding domain to the N-terminal portion of alpha-agglutinin. A 278-residue N-terminal peptide was inactive; therefore, the binding domain includes residues between 278 and 350. The segment of alpha-agglutinin between amino acid residues 217 and 308 showed significant structural and sequence similarity to a consensus sequence for immunoglobulin superfamily variable-type domains. The similarity of the alpha-agglutinin-binding domain to mammalian cell adhesion proteins suggests that this structure is a highly conserved feature of adhesion proteins in diverse eukaryotes.


Cells ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 715
Author(s):  
Tamara Tomanić ◽  
Claire Martin ◽  
Holly Stefen ◽  
Esmeralda Parić ◽  
Peter Gunning ◽  
...  

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.


2017 ◽  
Vol 65 (35) ◽  
pp. 7705-7712 ◽  
Author(s):  
Long Ding ◽  
Liying Wang ◽  
Zhipeng Yu ◽  
Sitong Ma ◽  
Zhiyang Du ◽  
...  

1970 ◽  
Vol 120 (2) ◽  
pp. 417-424 ◽  
Author(s):  
A. P. Fletcher ◽  
A. Neuberger ◽  
Wendy A. Ratcliffe

1. A revised amino acid and carbohydrate composition of human Tamm–Horsfall glycoprotein is presented. 2. No significant differences were obtained in the amino acid composition of Tamm–Horsfall glycoprotein isolated from patients with cystic fibrosis. 3. The glycoprotein was shown to possess a high half-cystine content of 1 per 11–12 amino acid residues, which has been confirmed by performic acid oxidation and S-alkylation with iodoacetate and iodoacetamide. No thiol groups were detected in the glycoprotein. 4. Treatment of the glycoprotein with 0.5m-sodium hydroxide at 4°C for 2 days did not release heterosaccharide material, which suggests that the predominant carbohydrate–protein linkages present are not of the O-glycosidic type. 5. No N-terminal amino acid was detected in the glycoprotein.


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