scholarly journals The Dual α-Amidation System in Scorpion Venom Glands

Toxins ◽  
2019 ◽  
Vol 11 (7) ◽  
pp. 425 ◽  
Author(s):  
Gustavo Delgado-Prudencio ◽  
Lourival D. Possani ◽  
Baltazar Becerril ◽  
Ernesto Ortiz
Keyword(s):  
Amino Acid ◽  
Enzymatic Activity ◽  
Biological Function ◽  
Scorpion Venom ◽  
Amino Acid Residues ◽  
Post Translational Modification ◽  
Proprotein Convertases ◽  
Functional Potential ◽  
Recognition Sites ◽  
Venom Glands

Many peptides in scorpion venoms are amidated at their C-termini. This post-translational modification is paramount for the correct biological function of ion channel toxins and antimicrobial peptides, among others. The discovery of canonical amidation sequences in transcriptome-derived scorpion proproteins suggests that a conserved enzymatic α-amidation system must be responsible for this modification of scorpion peptides. A transcriptomic approach was employed to identify sequences putatively encoding enzymes of the α-amidation pathway. A dual enzymatic α-amidation system was found, consisting of the membrane-anchored, bifunctional, peptidylglycine α-amidating monooxygenase (PAM) and its paralogs, soluble monofunctional peptidylglycine α-hydroxylating monooxygenase (PHMm) and peptidyl-α-hydroxyglycine α-amidating lyase (PALm). Independent genes encode these three enzymes. Amino acid residues responsible for ion coordination and enzymatic activity are conserved in these sequences, suggesting that the enzymes are functional. Potential endoproteolytic recognition sites for proprotein convertases in the PAM sequence indicate that PAM-derived soluble isoforms may also be expressed. Sequences potentially encoding proprotein convertases (PC1 and PC2), carboxypeptidase E (CPE), and other enzymes of the α-amidation pathway, were also found, confirming the presence of this pathway in scorpions.

Biological Function and Chemistry of Endothelin. A Review

1999 ◽  
Vol 64 (8) ◽  
pp. 1211-1252 ◽  
Author(s):  
Jan Hlaváček ◽  
Renáta Marcová
Keyword(s):  
Biological Activity ◽  
Amino Acid ◽  
Biological Function ◽  
Biological Properties ◽  
Structural Basis ◽  
Amino Acid Residues ◽  
Snake Venoms ◽  
Vasoactive Peptides ◽  
Physico Chemical ◽  
Endothelin A

The first part of this review deals with the biosynthesis and a biological function of strongly vasoactive peptides named endothelins (ETs) including vasoactive intestinal contractor. Where it was useful, snake venoms sarafotoxins which are structural endothelin derivatives, were also mentioned. In the second part, an attention is paid to structural basis of the ETs biological activity, with respect to alterations of amino acid residues in the parent peptides modifying the conformation and consequently the physico-chemical and biological properties in corresponding ETs analogs. Special attention is focussed on the area of ETs receptors and their interaction with peptide and non peptide agonists and antagonists, important in designing selective inhibitors of ETs receptors potentially applicable as drugs in a medicine. A review with 182 references.

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

2010 ◽  
Vol 432 (3) ◽  
pp. 557-566 ◽  
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.

scholarly journals Evidence that glutathione S-transferases B1B1 and B2B2 are the products of separate genes and that their expression in human liver is subject to inter-individual variation. Molecular relationships between the B1 and B2 subunits and other Alpha class glutathione S-transferases

1989 ◽  
Vol 264 (2) ◽  
pp. 437-445 ◽  
Author(s):  
J D Hayes ◽  
L A Kerr ◽  
A D Cronshaw
Keyword(s):  
Amino Acid ◽  
Human Liver ◽  
Sequence Data ◽  
Amino Acid Residues ◽  
Post Translational Modification ◽  
Amino Acid Sequence Analysis ◽  
Cdna Sequences ◽  
Glutathione S Transferases ◽  
Molecular Relationships ◽  
The Relationship

The Alpha class glutathione S-transferases (GSTs) in human liver are composed of polypeptides of Mr 25,900. These enzymes are dimeric, and two immunochemically distinct subunits, B1 and B2, have been described that combine to form GSTs B1B1, B1B2 and B2B2 [Stockman, Beckett & Hayes (1985) Biochem. J. 227, 457-465]. Gradient affinity elution from GSH-Sepharose has been used to resolve the three Alpha class GSTs, and this method has been applied to demonstrate marked inter-individual differences in the hepatic content of GSTs B1B1, B1B2 and B2B2. The B1 and B2 subunits can be resolved by reverse-phase h.p.l.c., and their elution positions suggest that they are equivalent to the alpha chi and alpha y h.p.l.c. peaks described by Ketterer and his colleagues [Ostlund Farrants, Meyer, Coles, Southan, Aitken, Johnson & Ketterer (1987) Biochem. J. 245, 423-428]. The B1 and B2 subunits have now been cleaved with CNBr and the fragments subjected to automated amino acid sequence analysis. The sequence data show that B1 and B2 subunits do not arise from post-translational modification, as had been previously believed for the hepatic Alpha class GSTs, but are instead the products of separate genes; B1 and B2 subunits were found to contain different amino acid residues at positions 88, 110, 111, 112, 116, 124 and 127. The relationship between the B1 and B2 subunits and the cloned GTH1 and GTH2 cDNA sequences [Rhoads, Zarlengo & Tu (1987) Biochem. Biophys. Res. Commun. 145, 474-481] is discussed.

scholarly journals An Activated Glutamate Residue Identified in Photosystem II at the Interface between the Manganese-stabilizing Subunit and the D2 Polypeptide

2007 ◽  
Vol 282 (38) ◽  
pp. 27802-27809 ◽  
Author(s):  
Sascha Rexroth ◽  
Catherine C. L. Wong ◽  
Jessica H. Park ◽  
John R. Yates ◽  
Bridgette A. Barry
Keyword(s):  
Amino Acid ◽  
Photosystem Ii ◽  
Oxygenic Photosynthesis ◽  
Photosynthetic Oxygen Evolution ◽  
Amino Acid Residues ◽  
Post Translational Modification ◽  
Steady State Rate ◽  
Reactive Groups ◽  
Psii Subunits

Photosystem II (PSII) catalyzes the oxidation of water during oxygenic photosynthesis. PSII is composed both of intrinsic subunits, such as D1, D2, and CP47, and extrinsic subunits, such as the manganese-stabilizing subunit (MSP). Previous work has shown that amines covalently bind to amino acid residues in the CP47, D1, and D2 subunits of plant and cyanobacterial PSII, and that these covalent reactions are prevented by the addition of chloride in plant preparations depleted of the 18- and 24-kDa extrinsic subunits. It has been proposed that these reactive groups are carbonyl-containing, post-translationally modified amino acid side chains (Ouellette, A. J. A., Anderson, L. B., and Barry, B. A. (1998) Proc. Natl. Acad. Sci. U. S. A. 95, 2204–2209 and Anderson, L. B., Ouellette, A. J. A., and Barry, B. A. (2000) J. Biol. Chem. 275, 4920–4927). To identify the amino acid binding site in the spinach D2 subunit, we have employed a biotin-amine labeling reagent, which can be used in conjunction with avidin affinity chromatography to purify biotinylated peptides from the PSII complex. Multidimensional chromato-graphic separation and multistage mass spectrometry localizes a novel post-translational modification in the D2 subunit to glutamate 303. We propose that this glutamate is activated for amine reaction by post-translational modification. Because the modified glutamate is located at a contact site between the D2 and manganese-stabilizing subunits, we suggest that the modification is important in vivo in stabilizing the interaction between these two PSII subunits. Consistent with this conclusion, mutations at the modified glutamate alter the steady-state rate of photosynthetic oxygen evolution.

scholarly journals Non-Protein Amino Acids: A Review of the Biosynthesis and Taxonomic Significance

2008 ◽  
Vol 3 (1) ◽  
pp. 1934578X0800300 ◽  
Author(s):  
E. Arthur Bell ◽  
Alison A. Watson ◽  
Robert J. Nash
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Biosynthetic Pathway ◽  
Amino Acid Residues ◽  
Taxonomic Significance ◽  
Post Translational Modification ◽  
Protein Amino Acid ◽  
Ancestral Form ◽  
Higher Taxa ◽  
Protein Amino Acids

The non-protein amino acids, with which we are concerned here, are not incorporated into the proteins of the organisms that synthesize them nor are their residues formed by the post-translational modification of protein amino acid residues. Non-protein amino acids are of value in the study of relationships between species and higher taxa of organisms because most of them are of restricted distribution. If a particular non-protein amino acid is only known to occur in a limited group of species which are related in other respects then it is probable that these species have all arisen from a common ancestral form in which the biosynthetic pathway to that particular non-protein amino acid already existed.

scholarly journals Making glycoproteins a little bit sweeter withPDB-REDO

2018 ◽  
Vol 74 (8) ◽  
pp. 463-472 ◽  
Author(s):  
Bart van Beusekom ◽  
Thomas Lütteke ◽  
Robbie P. Joosten
Keyword(s):  
Experimental Data ◽  
Amino Acid ◽  
Protein Data Bank ◽  
Model Building ◽  
Data Bank ◽  
Structure Model ◽  
Amino Acid Residues ◽  
Post Translational Modification ◽  
High Quality ◽  
Glycoprotein Structure

Glycosylation is one of the most common forms of protein post-translational modification, but is also the most complex. Dealing with glycoproteins in structure model building, refinement, validation and PDB deposition is more error-prone than dealing with nonglycosylated proteins owing to limitations of the experimental data and available software tools. Also, experimentalists are typically less experienced in dealing with carbohydrate residues than with amino-acid residues. The results of the reannotation and re-refinement byPDB-REDOof 8114 glycoprotein structure models from the Protein Data Bank are analyzed. The positive aspects of 3620 reannotations and subsequent refinement, as well as the remaining challenges to obtaining consistently high-quality carbohydrate models, are discussed.

scholarly journals Inhibitory Effect of an Acidic Peptide on the Activity of an Antimicrobial Peptide from the Scorpion Mesobuthus martensii Karsch

Molecules ◽  
2018 ◽  
Vol 23 (12) ◽  
pp. 3314 ◽  
Author(s):  
Wanxia Shi ◽  
Pengchen He ◽  
Xian-Chun Zeng ◽  
Weiwei Wu ◽  
Xiaoming Chen
Keyword(s):  
Staphylococcus Aureus ◽  
Structure Prediction ◽  
Secondary Structure Prediction ◽  
Coiled Coil ◽  
Inhibitory Effect ◽  
Scorpion Venom ◽  
Amino Acid Residues ◽  
Acidic Peptide ◽  
Venom Glands ◽  
Acidic Peptides

Highly acidic peptides with no disulfide bridges are widely present in the scorpion venoms; however, none of them has been functionally characterized so far. Here, we cloned the full-length cDNA of a short-chain highly acidic peptide (referred to as HAP-1) from a cDNA library made from the venom glands of the Chinese scorpion Mesobuthus martensii Karsch. HAP-1 contains 19 amino acid residues with a predicted IP value of 4.25. Acidic amino residues account for 33.3% of the total residues in the molecule of HAP-1. HAP-1 shows 76–98% identities to some scorpion venom peptides that have not yet been functionally characterized. Secondary structure prediction showed that HAP-1 contains a beta-sheet region (residues 9–17), and two coiled coil regions (residues 1–8 and 18–19) located at the N-terminal and C-terminal regions of the peptide, respectively. Antimicrobial assay showed that HAP-1 does not have any effect on the growth of the bacterium Staphylococcus aureus AB94004. However, it potently inhibits the antimicrobial activity of a 13-mer peptide from M. martensii Karsch against Staphylococcus aureus AB94004. This finding is the first characterization of the function of such highly acidic peptides from scorpions.

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