scholarly journals Ultrashort Cationic Lipopeptides–Effect of N-Terminal Amino Acid and Fatty Acid Type on Antimicrobial Activity and Hemolysis

Molecules ◽  
2020 ◽  
Vol 25 (2) ◽  
pp. 257 ◽  
Author(s):  
Damian Neubauer ◽  
Maciej Jaśkiewicz ◽  
Marta Bauer ◽  
Krzysztof Gołacki ◽  
Wojciech Kamysz
Keyword(s):  
Fatty Acid ◽  
Amino Acid ◽  
Antimicrobial Agents ◽  
Basic Amino Acid ◽  
Amino Acid Residues ◽  
Bacterial Strains ◽  
Fatty Acid Chain ◽  
N Terminus ◽  
Arginine Residues ◽  
The Impact

Ultrashort cationic lipopeptides (USCLs) are promising antimicrobial agents that hypothetically may be alternatively used to combat pathogens such as bacteria and fungi. In general, USCLs consist of fatty acid chains and a few basic amino acid residues. The main shortcoming of USCLs is their relatively high cytotoxicity and hemolytic activity. This study focuses on the impact of the hydrophobic fatty acid chain, on both antimicrobial and hemolytic activities. To learn more about this region, a series of USCLs with different straight-chain fatty acids (C8, C10, C12, C14) attached to the tripeptide with two arginine residues were synthesized. The amino acid at the N-terminal position was exchanged for proteinogenic and non-proteinogenic amino acid residues (24 in total). Moreover, the branched fatty acid residues were conjugated to N-terminus of a dipeptide with two arginine residues. All USCLs had C-terminal amides. USCLs were tested against reference bacterial strains (including ESKAPE group) and Candida albicans. The hemolytic potential was tested on human erythrocytes. Hydrophobicity of the compounds was evaluated by RP-HPLC. Shortening of the fatty acid chain and simultaneous addition of amino acid residue at N-terminus were expected to result in more selective and active compounds than those of the reference lipopeptides with similar lipophilicity. Hypothetically, this approach would also be beneficial to other antimicrobial peptides where N-lipidation strategy was used to improve their biological characteristics.

scholarly journals THE CORTICOSTATIC EFFECT OF HUMAN LACTOFERRIN DEPENDS ON THE AMINO ACID COMPOSITION OF THE N-TERMINUS OF THE MOLECULE

2019 ◽  
Vol 19 (1S) ◽  
pp. 159-160
Author(s):  
G M Aleshina
Keyword(s):  
Amino Acid ◽  
Cold Water ◽  
Intraperitoneal Administration ◽  
Corticosterone Level ◽  
Human Lactoferrin ◽  
Amino Acid Residues ◽  
Corticosterone Concentration ◽  
N Terminus ◽  
Arginine Residues ◽  
Induced Changes

The effect of various structural variants of human lactoferrin on stress-induced changes in the corticosterone level in the blood in rats was studied. A model of combined emotional and physical stress - swimming in cold water (1-4 °C) for 2 minutes. The level of corticosterone in plasma was determined by enzyme immunoassay. We have previously found that preventive intraperitoneal administration of native lactoferrin reduces the stress-induced increase in corticosterone concentration in the blood of rats 30 minutes after stress. This work shows that transgenic human lactoferrin, which lacks four arginine residues at the N-terminus, does not have this effect. The obtained results allow us to conclude about the key role of N-terminal amino acid residues in the implementation of the corticostatic activity of lactoferrin.

scholarly journals Primary- and secondary-structural analysis of a unique prokaryotic metallothionein from a Synechococcus sp. cyanobacterium

1988 ◽  
Vol 251 (3) ◽  
pp. 691-699 ◽  
Author(s):  
R W Olafson ◽  
W D McCubbin ◽  
C M Kay
Keyword(s):  
Amino Acid ◽  
Metal Binding ◽  
Helical Structure ◽  
Basic Amino Acid ◽  
Cysteine Residues ◽  
Amino Acid Residues ◽  
C Terminus ◽  
Empirical Relations ◽  
Heavy Metal Binding ◽  
Synechococcus Sp

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.

scholarly journals Rapid resensitization of ASIC2a is conferred by three amino acid residues in the N-terminus

IBRO Reports ◽  
2019 ◽  
Vol 6 ◽  
pp. S427-S428
Author(s):  
Jae Seung Lee ◽  
Hae-Jin Kweon ◽  
Byung-Chang Suh ◽  
Hyosang Lee
Keyword(s):  
Amino Acid ◽  
Amino Acid Residues ◽  
N Terminus

scholarly journals Novel antibody binding determinants on the capsid surface of serotype O foot-and-mouth disease virus

2014 ◽  
Vol 95 (5) ◽  
pp. 1104-1116 ◽  
Author(s):  
Amin S. Asfor ◽  
Sasmita Upadhyaya ◽  
Nick J. Knowles ◽  
Donald P. King ◽  
David J. Paton ◽  
...  
Keyword(s):  
Amino Acid ◽  
Guinea Pig ◽  
Foot And Mouth Disease ◽  
Mouth Disease ◽  
Amino Acid Residues ◽  
Serotype O ◽  
Antigenic Sites ◽  
Mouth Disease Virus ◽  
Foot And Mouth ◽  
The Impact

Five neutralizing antigenic sites have been described for serotype O foot-and-mouth disease viruses (FMDV) based on monoclonal antibody (mAb) escape mutant studies. However, a mutant virus selected to escape neutralization of mAb binding at all five sites was previously shown to confer complete cross-protection with the parental virus in guinea pig challenge studies, suggesting that amino acid residues outside the mAb binding sites contribute to antibody-mediated in vivo neutralization of FMDV. Comparison of the ability of bovine antisera to neutralize a panel of serotype O FMDV identified three novel putative sites at VP2-74, VP2-191 and VP3-85, where amino acid substitutions correlated with changes in sero-reactivity. The impact of these positions was tested using site-directed mutagenesis to effect substitutions at critical amino acid residues within an infectious copy of FMDV O1 Kaufbeuren (O1K). Recovered viruses containing additional mutations at VP2-74 and VP2-191 exhibited greater resistance to neutralization with both O1K guinea pig and O BFS bovine antisera than a virus that was engineered to include only mutations at the five known antigenic sites. The changes at VP2-74 and VP3-85 are adjacent to critical amino acids that define antigenic sites 2 and 4, respectively. However VP2-191 (17 Å away from VP2-72), located at the threefold axis and more distant from previously identified antigenic sites, exhibited the most profound effect. These findings extend our knowledge of the surface features of the FMDV capsid known to elicit neutralizing antibodies, and will improve our strategies for vaccine strain selection and rational vaccine design.

scholarly journals Identification of critical amino acid residues in the regulatory N-terminal domain of PMEL

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Susan M. Mitchell ◽  
Morven Graham ◽  
Xinran Liu ◽  
Ralf M. Leonhardt
Keyword(s):  
Amino Acid ◽  
Pigment Cell ◽  
Specific Protein ◽  
Single Amino Acid ◽  
Amyloid Formation ◽  
Amino Acid Residues ◽  
Proteolytic Fragment ◽  
The Core ◽  
N Terminus ◽  
In Cis

AbstractThe pigment cell-specific protein PMEL forms a functional amyloid matrix in melanosomes onto which the pigment melanin is deposited. The amyloid core consists of a short proteolytic fragment, which we have termed the core-amyloid fragment (CAF) and perhaps additional parts of the protein, such as the PKD domain. A highly O-glycosylated repeat (RPT) domain also derived from PMEL proteolysis associates with the amyloid and is necessary to establish the sheet-like morphology of the assemblies. Excluded from the aggregate is the regulatory N-terminus, which nevertheless must be linked in cis to the CAF in order to drive amyloid formation. The domain is then likely cleaved away immediately before, during, or immediately after the incorporation of a new CAF subunit into the nascent amyloid. We had previously identified a 21 amino acid long region, which mediates the regulatory activity of the N-terminus towards the CAF. However, many mutations in the respective segment caused misfolding and/or blocked PMEL export from the endoplasmic reticulum, leaving their phenotype hard to interpret. Here, we employ a saturating mutagenesis approach targeting the motif at single amino acid resolution. Our results confirm the critical nature of the PMEL N-terminal region and identify several residues essential for PMEL amyloidogenesis.

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